
Erratum: Resonance Effects in Photoemission Time Delays [Phys. Rev. Lett.115, 133001 (2015)] Phys. Rev. Lett. (IF 8.462) Pub Date : 20171120
M. Sabbar, S. Heuser, R. Boge, M. Lucchini, T. Carette, E. Lindroth, L. Gallmann, C. Cirelli, and U. KellerDOI:https://doi.org/10.1103/PhysRevLett.119.219901

Z3Parafermionic Zero Modes without Andreev Backscattering from the2/3Fractional Quantum Hall State Phys. Rev. Lett. (IF 8.462) Pub Date : 20171120
Yahya Alavirad, David Clarke, Amit Nag, and Jay D. SauParafermionic zero modes are a novel set of excitations displaying nonAbelian statistics somewhat richer than that of Majorana modes. These modes are predicted to occur when nearby fractional quantum Hall edge states are gapped by an interposed superconductor. Despite substantial experimental progress, we argue that the necessary crossed Andreev reflection in this arrangement is a challenging milestone to reach. We propose a superconducting quantum dot array structure on a fractional quantum Hall edge that can lead to parafermionic zero modes from coherent superconducting forward scattering on a quantum Hall edge. Such coherent forward scattering has already been demonstrated in recent experiments. We show that for a spinsinglet superconductor interacting with loops of spin unpolarized 2 / 3 fractional quantum edge, even an array size of order 10 should allow one to systematically tune into a parafermionic degeneracy.

Thermodynamic Evidence for the FuldeFerrellLarkinOvchinnikov State in theKFe2As2Superconductor Phys. Rev. Lett. (IF 8.462) Pub Date : 20171120
Changwoo Cho, Jonathan Haiwei Yang, Noah F. Q. Yuan, Junying Shen, Thomas Wolf, and Rolf LortzWe investigate the magnetic phase diagram near the upper critical field of KFe 2 As 2 by magnetic torque and specific heat experiments using a highresolution piezorotary positioner to precisely control the parallel alignment of the magnetic field with respect to the FeAs layers. We observe a clear double transition when the field is strictly aligned in the plane and a characteristic upturn of the upper critical field line, which goes far beyond the Pauli limit at 4.8 T. This provides firm evidence that a FuldeFerrellLarkinOvchinnikov state exists in this ironbased KFe 2 As 2 superconductor.

Observation of Bogoliubov Band Hybridization in the Optimally Doped TrilayerBi2Sr2Ca2Cu3O10+δ Phys. Rev. Lett. (IF 8.462) Pub Date : 20171120
So Kunisada, Shintaro Adachi, Shiro Sakai, Nae Sasaki, Mitsuhiro Nakayama, Shuntaro Akebi, Kenta Kuroda, Takao Sasagawa, Takao Watanabe, Shik Shin, and Takeshi Kondo 
Correlated ThreeDimensional Imaging of Dislocations: Insights into the Onset of Thermal Slip in Semiconductor Wafers Phys. Rev. Lett. (IF 8.462) Pub Date : 20171120
D. Hänschke, A. Danilewsky, L. Helfen, E. Hamann, and T. Baumbach 
Instabilities of Jammed Packings of Frictionless Spheres Under Load Phys. Rev. Lett. (IF 8.462) Pub Date : 20171120
Ning Xu, Andrea J. Liu, and Sidney R. NagelWe consider the contribution to the density of vibrational states and the distribution of energy barrier heights of incipient instabilities in a glass modeled by a jammed packing of spheres. On approaching an instability, the frequency of a normal mode and the height of the energy barrier to cross into a new ground state both vanish. These instabilities produce a contribution to the density of vibrational states that scales as ω 3 at low frequencies ω , and a contribution to the distribution of energy barriers Δ H that scales as Δ H − 1 / 3 at low barrier heights.

Correlation between Local Structure Order and Spatial Heterogeneity in a Metallic Glass Phys. Rev. Lett. (IF 8.462) Pub Date : 20171120
Fan Zhu, Akihiko Hirata, Pan Liu, Shuangxi Song, Yuan Tian, Jiuhui Han, Takeshi Fujita, and Mingwei ChenAlthough nanoscale spatial heterogeneity of metallic glasses has been demonstrated by extensive experimental and theoretical investigations, the nature of spatial heterogeneity remains poorly known owing to the absence of a structural depiction of the inhomogeneity from experimental insight. Here we report the experimental characterization of the spatial heterogeneity of a metallic glass by utilizing stateoftheart angstrombeam electron diffraction and scanning transmission electron microscopy. The subnanoscale electron diffraction reveals that the nanoscale spatial heterogeneity and corresponding density fluctuation have a close correlation with the local structure variation from icosahedronlike to tetragonal crystallike order. The structural insights of spatial heterogeneity have important implications in understanding the properties and dynamics of metallic glasses.

Superfluid Filaments of Dipolar Bosons in Free Space Phys. Rev. Lett. (IF 8.462) Pub Date : 20171120
Fabio Cinti, Alberto Cappellaro, Luca Salasnich, and Tommaso MacrìWe systematically investigate the zero temperature phase diagram of bosons interacting via dipolar interactions in three dimensions in free space via path integral Monte Carlo simulations with a few hundreds of particles and periodic boundary conditions based on the worm algorithm. Upon increasing the strength of the dipolar interaction and at sufficiently high densities we find a wide region where filaments are stabilized along the direction of the external field. Most interestingly by computing the superfluid fraction we conclude that the superfluidity is anisotropic and is greatly suppressed along the orthogonal plane. Finally, we perform simulations at finite temperature confirming the stability of the filaments against thermal fluctuations and provide an estimate of the superfluid fraction in the weak coupling limit in the framework of the Landau twofluid model.

Double Contact During Drop Impact on a Solid Under Reduced Air Pressure Phys. Rev. Lett. (IF 8.462) Pub Date : 20171120
Er Qiang Li, Kenneth R. Langley, Yuan Si Tian, Peter D. Hicks, and Sigurdur T. ThoroddsenDrops impacting on solid surfaces entrap small bubbles under their centers, owing to the lubrication pressure which builds up in the thin intervening air layer. We use ultrahighspeed interference imaging, at 5 Mfps, to investigate how this air layer changes when the ambient air pressure is reduced below atmospheric. Both the radius and the thickness of the air disc become smaller with reduced air pressure. Furthermore, we find the radial extent of the air disc bifurcates, when the compressibility parameter exceeds ∼ 25 . This bifurcation is also imprinted onto some of the impacts, as a double contact. In addition to the central air disc inside the first ring contact, this is immediately followed by a second ring contact, which entraps an outer toroidal strip of air, which contracts into a ring of bubbles. We find this occurs in a regime where Navier slip, due to rarefied gas effects, enhances the rate gas can escape from the path of the droplet.

What Controls Thermoosmosis? Molecular Simulations Show the Critical Role of Interfacial Hydrodynamics Phys. Rev. Lett. (IF 8.462) Pub Date : 20171120
Li Fu, Samy Merabia, and Laurent JolyThermoosmotic and related thermophoretic phenomena can be found in many situations from biology to colloid science, but the underlying molecular mechanisms remain largely unexplored. Using molecular dynamics simulations, we measure the thermoosmosis coefficient by both mechanocaloric and thermoosmotic routes, for different solidliquid interfacial energies. The simulations reveal, in particular, the crucial role of nanoscale interfacial hydrodynamics. For nonwetting surfaces, thermoosmotic transport is largely amplified by hydrodynamic slip at the interface. For wetting surfaces, the position of the hydrodynamic shear plane plays a key role in determining the amplitude and sign of the thermoosmosis coefficient. Finally, we measure a giant thermoosmotic response of the watergraphene interface, which we relate to the very low interfacial friction displayed by this system. These results open new perspectives for the design of efficient functional interfaces for, e.g., wasteheat harvesting.

Three Dimensional Photonic Dirac Points in Metamaterials Phys. Rev. Lett. (IF 8.462) Pub Date : 20171120
Qinghua Guo, Biao Yang, Lingbo Xia, Wenlong Gao, Hongchao Liu, Jing Chen, Yuanjiang Xiang, and Shuang ZhangTopological semimetals, representing a new topological phase that lacks a full band gap in bulk states and exhibiting nontrivial topological orders, recently have been extended to photonic systems, predominantly in photonic crystals and to a lesser extent metamaterials. Photonic crystal realizations of Dirac degeneracies are protected by various space symmetries, where Bloch modes span the spin and orbital subspaces. Here, we theoretically show that Dirac points can also be realized in effective media through the intrinsic degrees of freedom in electromagnetism under electromagnetic duality. A pair of spinpolarized Fermiarclike surface states is observed at the interface between air and the Dirac metamaterials. Furthermore, eigenreflection fields show the decoupling process from a Dirac point to two Weyl points. We also find the topological correlation between a Dirac point and vortex or vector beams in classical photonics. The experimental feasibility of our scheme is demonstrated by designing a realistic metamaterial structure. The theoretical proposal of the photonic Dirac point lays the foundation for unveiling the connection between intrinsic physics and global topology in electromagnetism.

Cavity QED Engineering of Spin Dynamics and Squeezing in a Spinor Gas Phys. Rev. Lett. (IF 8.462) Pub Date : 20171120
Stuart J. Masson, M. D. Barrett, and Scott ParkinsWe propose a method for engineering spin dynamics in ensembles of integerspin atoms confined within a highfinesse optical cavity. Our proposal uses cavityassisted Raman transitions to engineer a Dicke model for integerspin atoms, which, in a dispersive limit, reduces to effective atomatom interactions within the ensemble. This scheme offers a promising and flexible new avenue for the exploration of a wide range of spinor manybody physics. As an example of this, we present results showing that this method can be used to generate spinnematic squeezing in an ensemble of spin1 atoms. With realistic parameters, the scheme should enable substantial squeezing on time scales much shorter than current experiments with spin1 BoseEinstein condensates.

Threshold and Jet Radius Joint Resummation for SingleInclusive Jet Production Phys. Rev. Lett. (IF 8.462) Pub Date : 20171120
Xiaohui Liu, SvenOlaf Moch, and Felix RingerWe present the first threshold and jet radius jointly resummed cross section for singleinclusive hadronic jet production. We work at nexttoleading logarithmic accuracy and our framework allows for a systematic extension beyond the currently achieved precision. Longstanding numerical issues are overcome by performing the resummation directly in momentum space within soft collinear effective theory. We present the first numerical results for the LHC and observe an improved description of the available data. Our results are of immediate relevance for LHC precision phenomenology including the extraction of parton distribution functions and the QCD strong coupling constant.

Asymptotic Safety Guaranteed in Supersymmetry Phys. Rev. Lett. (IF 8.462) Pub Date : 20171120
Andrew D. Bond and Daniel F. LitimWe explain how asymptotic safety arises in fourdimensional supersymmetric gauge theories. We provide asymptotically safe supersymmetric gauge theories together with their superconformal fixed points, R charges, phase diagrams, and UVIR connecting trajectories. Strict perturbative control is achieved in a Veneziano limit. Consistency with unitarity and the a theorem is established. We find that supersymmetry enhances the predictivity of asymptotically safe theories.

Probing SubGeV Mass Strongly Interacting Dark Matter with a LowThreshold Surface Experiment Phys. Rev. Lett. (IF 8.462) Pub Date : 20171120
Jonathan H. DavisUsing data from the ν cleus detector, based on the surface of Earth, we place constraints on dark matter in the form of strongly interacting massive particles (SIMPs) which interact with nucleons via nuclearscale cross sections. For large SIMPnucleon cross sections, the sensitivity of traditional direct dark matter searches using underground experiments is limited by the energy loss experienced by SIMPs, due to scattering with the rock overburden and experimental shielding on their way to the detector apparatus. Hence, a surfacebased experiment is ideal for a SIMP search, despite the much larger background resulting from the lack of shielding. We show using data from a recent surface run of a lowthreshold cryogenic detector that values of the SIMPnucleon cross section up to approximately 10 − 27 cm 2 can be excluded for SIMPs with masses above 100 MeV.

Hořava Gravity is Asymptotically Free in2+1Dimensions Phys. Rev. Lett. (IF 8.462) Pub Date : 20171120
Andrei O. Barvinsky, Diego Blas, Mario HerreroValea, Sergey M. Sibiryakov, and Christian F. SteinwachsWe compute the β functions of marginal couplings in projectable Hořava gravity in 2 + 1 spacetime dimensions. We show that the renormalization group flow has an asymptotically free fixed point in the ultraviolet (UV), establishing the theory as a UVcomplete model with dynamical gravitational degrees of freedom. Therefore, this theory may serve as a toy model to study fundamental aspects of quantum gravity. Our results represent a step forward towards understanding the UV properties of realistic versions of Hořava gravity.

Efficient LowOrder Approximation of FirstPassage Time Distributions Phys. Rev. Lett. (IF 8.462) Pub Date : 20171120
David Schnoerr, Botond Cseke, Ramon Grima, and Guido SanguinettiWe consider the problem of computing firstpassage time distributions for reaction processes modeled by master equations. We show that this generally intractable class of problems is equivalent to a sequential Bayesian inference problem for an auxiliary observation process. The solution can be approximated efficiently by solving a closed set of coupled ordinary differential equations (for the loworder moments of the process) whose size scales with the number of species. We apply it to an epidemic model and a trimerization process and show good agreement with stochastic simulations.

Nonlocal Entanglement of 1D Thermal States Induced by Fermion Exchange Statistics Phys. Rev. Lett. (IF 8.462) Pub Date : 20171120
YeJe Park, Jeongmin Shim, S.S. B. Lee, and H.S. SimWhen two identical fermions exchange their positions, their wave function gains a phase factor of − 1 . We show that this distanceindependent effect can induce nonlocal entanglement in onedimensional (1D) electron systems having Majorana fermions at the ends. It occurs in the system bulk and has a nontrivial temperature dependence. In a system having a single Majorana fermion at each end, the nonlocal entanglement has a Bellstate form at zero temperature and decays as the temperature increases, vanishing suddenly at a certain finite temperature. In a system having two Majorana fermions at each end, it is in a clusterstate form and its nonlocality is more noticeable at a finite temperature. By contrast, the thermal states of corresponding 1D spins do not have nonlocal entanglement.

Topological Edge States in Periodically Driven TrappedIon Chains Phys. Rev. Lett. (IF 8.462) Pub Date : 20171120
Pedro Nevado, Samuel FernándezLorenzo, and Diego PorrasTopological insulating phases are primarily associated with condensedmatter systems, which typically feature shortrange interactions. Nevertheless, many realizations of quantum matter can exhibit longrange interactions, and it is still largely unknown the effect that these latter may exert upon the topological phases. In this Letter, we investigate the SuSchriefferHeeger topological insulator in the presence of longrange interactions. We show that this model can be readily realized in quantum simulators with trapped ions by means of a periodic driving. Our results indicate that the localization of the associated edge states is enhanced by the longrange interactions, and that the localized components survive within the ground state of the model. These effects could be easily confirmed in current stateoftheart experimental implementations.

Transition to Turbulent Dynamo Saturation Phys. Rev. Lett. (IF 8.462) Pub Date : 20171117
Kannabiran Seshasayanan, Basile Gallet, and Alexandros AlexakisWhile the saturated magnetic energy is independent of viscosity in dynamo experiments, it remains viscosity dependent in stateoftheart 3D direct numerical simulations (DNS). Extrapolating such viscous scaling laws to realistic parameter values leads to an underestimation of the magnetic energy by several orders of magnitude. The origin of this discrepancy is that fully 3D DNS cannot reach low enough values of the magnetic Prandtl number Pm. To bypass this limitation and investigate dynamo saturation at very low Pm, we focus on the vicinity of the dynamo threshold in a rapidly rotating flow: the velocity field then depends on two spatial coordinates only, while the magnetic field consists of a single Fourier mode in the third direction. We perform numerical simulations of the resulting set of reduced equations for Pm down to 2 × 10 − 5 . This parameter regime is currently out of reach to fully 3D DNS. We show that the magnetic energy transitions from a highPm viscous scaling regime to a lowPm turbulent scaling regime, the latter being independent of viscosity. The transition to the turbulent saturation regime occurs at a low value of the magnetic Prandtl number, Pm ≃ 10 − 3 , which explains why it has been overlooked by numerical studies so far.

Forced Imbibition in Porous Media: A Fourfold Scenario Phys. Rev. Lett. (IF 8.462) Pub Date : 20171117
Céleste Odier, Bertrand Levaché, Enric SantanachCarreras, and Denis BartoloWe establish a comprehensive description of the patterns formed when a wetting liquid displaces a viscous fluid confined in a porous medium. Building on model microfluidic experiments, we evidence four imbibition scenarios all yielding different largescale morphologies. Combining highresolution imaging and confocal microscopy, we show that they originate from two liquidentrainment transitions and a RayleighPlateau instability at the pore scale. Finally, we demonstrate and explain the longtime coarsening of the resulting patterns.

Superconductivity at the PolarNonpolar Phase Boundary of SnP with an Unusual Valence State Phys. Rev. Lett. (IF 8.462) Pub Date : 20171117
M. Kamitani, M. S. Bahramy, T. Nakajima, C. Terakura, D. Hashizume, T. Arima, and Y. Tokura 
Multiple Types of Topological Fermions in Transition Metal Silicides Phys. Rev. Lett. (IF 8.462) Pub Date : 20171117
Peizhe Tang, Quan Zhou, and ShouCheng ZhangExotic massless fermionic excitations with nonzero Berry flux, other than the Dirac and Weyl fermions, could exist in condensed matter systems under the protection of crystalline symmetries, such as spin1 excitations with threefold degeneracy and spin 3 / 2 RaritaSchwingerWeyl fermions. Herein, by using the ab initio density functional theory, we show that these unconventional quasiparticles coexist with typeI and typeII Weyl fermions in a family of transition metal silicides, including CoSi, RhSi, RhGe, and CoGe, when spinorbit coupling is considered. Their nontrivial topology results in a series of extensive Fermi arcs connecting projections of these bulk excitations on the side surface, which is confirmed by (001) surface electronic spectra of CoSi. In addition, these stable arc states exist within a wide energy window around the Fermi level, which makes them readily accessible in angleresolved photoemission spectroscopy measurements.

Unconventional Chiral Fermions and Large Topological Fermi Arcs in RhSi Phys. Rev. Lett. (IF 8.462) Pub Date : 20171117
Guoqing Chang, SuYang Xu, Benjamin J. Wieder, Daniel S. Sanchez, ShinMing Huang, Ilya Belopolski, TayRong Chang, Songtian Zhang, Arun Bansil, Hsin Lin, and M. Zahid HasanThe theoretical proposal of chiral fermions in topological semimetals has led to a significant effort towards their experimental realization. In particular, the Fermi surfaces of chiral semimetals carry quantized Chern numbers, making them an attractive platform for the observation of exotic transport and optical phenomena. While the simplest example of a chiral fermion in condensed matter is a conventional  C  = 1 Weyl fermion, recent theoretical works have proposed a number of unconventional chiral fermions beyond the standard model which are protected by unique combinations of topology and crystalline symmetries. However, materials candidates for experimentally probing the transport and response signatures of these unconventional fermions have thus far remained elusive. In this Letter, we propose the RhSi family in space group No. 198 as the ideal platform for the experimental examination of unconventional chiral fermions. We find that RhSi is a fillingenforced semimetal that features near its Fermi surface a chiral double sixfolddegenerate spin1 Weyl node at R and a previously uncharacterized fourfolddegenerate chiral fermion at Γ . Each unconventional fermion displays Chern number ± 4 at the Fermi level. We also show that RhSi displays the largest possible momentum separation of compensative chiral fermions, the largest proposed topologically nontrivial energy window, and the longest possible Fermi arcs on its surface. We conclude by proposing signatures of an exotic bulk photogalvanic response in RhSi.

Ultrafast Generation of Unconventional{001}Loops in Si Phys. Rev. Lett. (IF 8.462) Pub Date : 20171117
Luis A. Marqués, María Aboy, Iván Santos, Pedro López, Fuccio Cristiano, Antonino La Magna, Karim Huet, Toshiyuki Tabata, and Lourdes PelazUltrafast laser annealing of ion implanted Si has led to thermodynamically unexpected large { 001 } selfinterstitial loops, and the failure of Ostwald ripening models for describing selfinterstitial cluster growth. We have carried out molecular dynamics simulations in combination with focused experiments in order to demonstrate that at temperatures close to the melting point, selfinterstitial rich Si is driven into dense liquidlike droplets that are highly mobile within the solid crystalline Si matrix. These liquid droplets grow by a coalescence mechanism and eventually transform into { 001 } loops through a liquidtosolid phase transition in the nanosecond time scale.

Experimental Observation of Convective Cell Formation due to a Fast Wave Antenna in the Large Plasma Device Phys. Rev. Lett. (IF 8.462) Pub Date : 20171117
M. J. Martin, W. Gekelman, B. Van Compernolle, P. Pribyl, and T. CarterAn experiment in a linear device, the Large Plasma Device, is used to study sheaths caused by an actively powered radio frequency (rf) antenna. The rf antenna used in the experiment consists of a single current strap recessed inside a copper box enclosure without a Faraday screen. A large increase in the plasma potential was observed along magnetic field lines that connect to the antenna limiter. The electric field from the spatial variation of the rectified plasma potential generated E → × B → 0 flows, often referred to as convective cells. The presence of the flows generated by these potentials is confirmed by Mach probes. The observed convective cell flows are seen to cause the plasma in front of the antenna to flow away and cause a density modification near the antenna edge. These can cause hot spots and damage to the antenna and can result in a decrease in the ion cyclotron range of frequencies antenna coupling.

Unexpected Sensitivity of Nitrogen Ions Superradiant Emission on Pump Laser Wavelength and Duration Phys. Rev. Lett. (IF 8.462) Pub Date : 20171117
Yi Liu, Pengji Ding, Neven Ibrakovic, Samuel Bengtsson, Shihua Chen, Rostyslav Danylo, Emma R. Simpson, Esben W. Larsen, Xiang Zhang, Zhengquan Fan, Aurélien Houard, Johan Mauritsson, Anne L’Huillier, Cord L. Arnold, Songlin Zhuang, Vladimir Tikhonchuk, and André MysyrowiczNitrogen molecules in ambient air exposed to an intense nearinfrared femtosecond laser pulse give rise to cavityfree superradiant emission at 391.4 and 427.8 nm. An unexpected pulse durationdependent cyclic variation of the superradiance intensity is observed when the central wavelength of the femtosecond pump laser pulse is finely tuned between 780 and 820 nm, and no signal occurs at the resonant wavelength of 782.8 nm ( 2 ω 782.8 nm = ω 391.4 nm ). On the basis of a semiclassical recollision model, we show that an interference of dipolar moments of excited ions created by electron recollisions explains this behavior.

Topological EdgeState Manifestation of Interacting 2D Condensed BosonLattice Systems in a Harmonic Trap Phys. Rev. Lett. (IF 8.462) Pub Date : 20171117
Bogdan Galilo, Derek K. K. Lee, and Ryan BarnettIn this Letter, it is shown that interactions can facilitate the emergence of topological edge states of quantumdegenerate bosonic systems in the presence of a harmonic potential. This effect is demonstrated with the concrete model of a hexagonal lattice populated by spinone bosons under a synthetic gauge field. In fermionic or noninteracting systems, the presence of a harmonic trap can obscure the observation of edge states. For our system with weakly interacting bosons in the ThomasFermi regime, we can clearly see a topological band structure with a band gap traversed by edge states. We also find that the number of edge states crossing the gap is increased in the presence of a harmonic trap, and the edge modes experience an energy shift while traversing the first Brillouin zone which is related to the topological properties of the system. We find an analytical expression for the edgestate energies and our comparison with numerical computation shows excellent agreement.

LongLived Inverse Chirp Signals from CoreCollapse in Massive ScalarTensor Gravity Phys. Rev. Lett. (IF 8.462) Pub Date : 20171117
Ulrich Sperhake, Christopher J. Moore, Roxana Rosca, Michalis Agathos, Davide Gerosa, and Christian D. OttThis Letter considers stellar core collapse in massive scalartensor theories of gravity. The presence of a mass term for the scalar field allows for dramatic increases in the radiated gravitational wave signal. There are several potential smoking gun signatures of a departure from general relativity associated with this process. These signatures could show up within existing LIGOVirgo searches.

DoubleExchange Interaction in Optically Induced Nonequilibrium State: A Conversion from Ferromagnetic to Antiferromagnetic Structure Phys. Rev. Lett. (IF 8.462) Pub Date : 20171116
Atsushi Ono and Sumio Ishihara 
Block Analysis for the Calculation of Dynamic and Static Length Scales in GlassForming Liquids Phys. Rev. Lett. (IF 8.462) Pub Date : 20171116
Saurish Chakrabarty, Indrajit Tah, Smarajit Karmakar, and Chandan DasguptaWe present block analysis, an efficient method of performing finitesize scaling for obtaining the length scale of dynamic heterogeneity and the pointtoset length scale for generic glassforming liquids. This method involves considering blocks of varying sizes embedded in a system of a fixed (large) size. The length scale associated with dynamic heterogeneity is obtained from a finitesize scaling analysis of the dependence of the fourpoint dynamic susceptibility on the block size. The block size dependence of the variance of the α relaxation time yields the static pointtoset length scale. The values of the obtained length scales agree quantitatively with those obtained from other conventional methods. This method provides an efficient experimental tool for studying the growth of length scales in systems such as colloidal glasses for which performing finitesize scaling by carrying out experiments for varying system sizes may not be feasible.

Magnetospheric Multiscale Observation of Plasma VelocitySpace Cascade: Hermite Representation and Theory Phys. Rev. Lett. (IF 8.462) Pub Date : 20171116
S. Servidio, A. Chasapis, W. H. Matthaeus, D. Perrone, F. Valentini, T. N. Parashar, P. Veltri, D. Gershman, C. T. Russell, B. Giles, S. A. Fuselier, T. D. Phan, and J. BurchPlasma turbulence is investigated using unprecedented highresolution ion velocity distribution measurements by the Magnetospheric Multiscale mission (MMS) in the Earth’s magnetosheath. This novel observation of a highly structured particle distribution suggests a cascadelike process in velocity space. Complex velocity space structure is investigated using a threedimensional Hermite transform, revealing, for the first time in observational data, a powerlaw distribution of moments. In analogy to hydrodynamics, a Kolmogorov approach leads directly to a range of predictions for this phasespace transport. The scaling theory is found to be in agreement with observations. The combined use of stateoftheart MMS data sets, novel implementation of a Hermite transform method, and scaling theory of the velocity cascade opens new pathways to the understanding of plasma turbulence and the crucial velocity space features that lead to dissipation in plasmas.

Revision of Bubble Bursting: Universal Scaling Laws of Top Jet Drop Size and Speed Phys. Rev. Lett. (IF 8.462) Pub Date : 20171116
Alfonso M. GañánCalvoThe collapse of a bubble of radius R o at the surface of a liquid generating a liquid jet and a subsequent first drop of radius R is universally scaled using the Ohnesorge number Oh = μ / ( ρ σ R o ) 1 / 2 and a critical value Oh * below which no droplet is ejected; ρ , σ , and μ are the liquid density, surface tension, and viscosity, respectively. First, a flow field analysis at ejection yields the scaling of R with the jet velocity V as R / l μ ∼ ( V / V μ ) − 5 / 3 , where l μ = μ 2 / ( ρ σ ) and V μ = σ / μ . This resolves the scaling problem of curvature reversal, a prelude to jet formation. In addition, the energy necessary for the ejection of a jet with a volume and averaged velocity proportional to R o R 2 and V , respectively, comes from the energy excess from the total available surface energy, proportional to σ R o 2 , minus the one dissipated by viscosity, proportional to μ ( σ R o 3 / ρ ) 1 / 2 . Using the scaling variable φ = ( Oh * − Oh ) Oh − 2 , it yields V / V μ = k v φ − 3 / 4 and R / l μ = k d φ 5 / 4 , which collapse published data since 1954 and resolve the scaling of R and V with k v = 16 , k d = 0.6 , and Oh * = 0.043 when gravity effects are negligible.

Persistence and Lifelong Fidelity of Phase Singularities in Optical Random Waves Phys. Rev. Lett. (IF 8.462) Pub Date : 20171116
L. De Angelis, F. Alpeggiani, A. Di Falco, and L. KuipersPhase singularities are locations where light is twisted like a corkscrew, with positive or negative topological charge depending on the twisting direction. Among the multitude of singularities arising in random wave fields, some can be found at the same location, but only when they exhibit opposite topological charge, which results in their mutual annihilation. New pairs can be created as well. With nearfield experiments supported by theory and numerical simulations, we study the persistence and pairing statistics of phase singularities in random optical fields as a function of the excitation wavelength. We demonstrate how such entities can encrypt fundamental properties of the random fields in which they arise.

Propagation Dynamics Associated with Resonant Magnetic Perturbation Fields in HighConfinement Mode Plasmas inside the KSTAR Tokamak Phys. Rev. Lett. (IF 8.462) Pub Date : 20171115
W. W. Xiao, T. E. Evans, G. R. Tynan, S. W. Yoon, Y. M. Jeon, W. H. Ko, Y. U. Nam, Y. K. Oh, and KSTAR teamThe propagation dynamics of resonant magnetic perturbation fields in KSTAR H mode plasmas with injection of small edge perturbations produced by a supersonic molecular beam injection is reported for the first time. The results show that the perturbation field first excites a plasma response on the q = 3 magnetic surface and then propagates inward to the q = 2 surface with a radially averaged propagation velocity of resonant magnetic perturbations field equal to 32.5 m / s . As a result, the perturbation field brakes the toroidal rotation on the q = 3 surface first causing a momentum transport perturbation that propagates both inward and outward. A higher density fluctuation level is observed. The propagation velocity of the resonant magnetic perturbations field is larger than the radial propagation velocity of the perturbation in the toroidal rotation.

Optimal Design of Experiments by Combining Coarse and Fine Measurements Phys. Rev. Lett. (IF 8.462) Pub Date : 20171116
Alpha A. Lee, Michael P. Brenner, and Lucy J. ColwellIn many contexts, it is extremely costly to perform enough highquality experimental measurements to accurately parametrize a predictive quantitative model. However, it is often much easier to carry out large numbers of experiments that indicate whether each sample is above or below a given threshold. Can many such categorical or “coarse” measurements be combined with a much smaller number of highresolution or “fine” measurements to yield accurate models? Here, we demonstrate an intuitive strategy, inspired by statistical physics, wherein the coarse measurements are used to identify the salient features of the data, while the fine measurements determine the relative importance of these features. A linear model is inferred from the fine measurements, augmented by a quadratic term that captures the correlation structure of the coarse data. We illustrate our strategy by considering the problems of predicting the antimalarial potency and aqueous solubility of small organic molecules from their 2D molecular structure.

Wall Slip of SoftJammed Systems: A Generic Simple Shear Process Phys. Rev. Lett. (IF 8.462) Pub Date : 20171116
X. Zhang, E. Lorenceau, P. Basset, T. Bourouina, F. Rouyer, J. Goyon, and P. CoussotFrom wellcontrolled long creep tests, we show that the residual apparent yield stress observed with softjammed systems along smooth surfaces is an artifact due to edge effects. By removing these effects, we can determine the stress solely associated with steadystate wall slip below the material yield stress. This stress is found to vary linearly with the slip velocity for a wide range of materials whatever the structure, the interaction types between the elements and with the wall, and the concentration. Thus, wall slip results from the laminar flow of some given free liquid volume remaining between the (rough) jammed structure formed by the elements and the smooth wall. This phenomenon may be described by the simple shear flow in a Newtonian liquid layer of uniform thickness. For various systems, this equivalent thickness varies in a narrow range ( 35 ± 15 nm ).

Band Structure and Contact Resistance of Carbon Nanotubes Deformed by a Metal Contact Phys. Rev. Lett. (IF 8.462) Pub Date : 20171116
Roohollah Hafizi, Jerry Tersoff, and Vasili PerebeinosCapillary and van der Waals forces cause nanotubes to deform or even collapse under metal contacts. Using ab initio band structure calculations, we find that these deformations reduce the band gap by as much as 30%, while fully collapsed nanotubes become metallic. Moreover, degeneracy lifting due to the broken axial symmetry, and wave functions mismatch between the fully collapsed and the round portions of a CNT, lead to a 3 times higher contact resistance. The latter we demonstrate by contact resistance calculations within the tightbinding approach.

Favorable Concurrence of Static and Dynamic Phenomena at the Morphotropic Phase Boundary ofxBiNi0.5Zr0.5O3−(1−x)PbTiO3 Phys. Rev. Lett. (IF 8.462) Pub Date : 20171116
K. Datta, R. B. Neder, J. Chen, J. C. Neuefeind, and B. MihailovaWe reveal that concurrent events of inherent entropy boosting and increased synchronization between A  and B site cation vibrations of an A B O 3 type perovskite structure give rise to a larger piezoelectric response in a ferroelectric system at its morphotropic phase boundary (MPB). It is further evident that the superior piezoelectric properties of x BiNi 0.5 Zr 0.5 O 3 − ( 1 − x ) PbTiO 3 in comparison to x BiNi 0.5 Ti 0.5 O 3 − ( 1 − x ) PbTiO 3 are due to the absolute flattening of the local potentials for all ferroelectrically active cations with a higher spontaneous polarization at the MPB. These distinctive features are discovered from the analyses of neutron pair distribution functions and Raman scattering data at ambient conditions, which are particularly sensitive to mesoscopicscale structural correlations. Altogether this uncovers more fundamental structureproperty connections for ferroelectric systems exhibiting a MPB, and thereby has a critical impact in contriving efficient novel materials.

Angular Momentum of Topologically Structured Darkness Phys. Rev. Lett. (IF 8.462) Pub Date : 20171116
Samuel N. Alperin and Mark E. SiemensWe theoretically analyze and experimentally measure the extrinsic angular momentum contribution of topologically structured darkness found within fractional vortex beams, and show that this structured darkness can be explained by evanescent waves at phase discontinuities in the generating optic. We also demonstrate the first direct measurement of the intrinsic orbital angular momentum of light with both intrinsic and extrinsic angular momentum, and explain why the total orbital angular momenta of fractional vortices do not match the winding number of their generating phases.

Probing Positron Cooling in Noble Gases via AnnihilationγSpectra Phys. Rev. Lett. (IF 8.462) Pub Date : 20171116
D. G. Greenγ spectra for positron annihilation in noblegas atoms are calculated using manybody theory for positron momenta up to the positroniumformation threshold. These data are used, together with timeevolving positronmomentum distributions determined in the preceding Letter [Phys. Rev. Lett. 119, 203403 (2017)], to calculate the timevarying γ spectra produced during positron cooling in noble gases. The γ spectra and their S ¯ and W ¯ shape parameters are shown to be sensitive probes of the time evolution of the positron momentum distribution and thus provide a means of studying positron cooling that is complementary to positron lifetime spectroscopy.

Positron Cooling and Annihilation in Noble Gases Phys. Rev. Lett. (IF 8.462) Pub Date : 20171116
D. G. GreenPositron cooling and annihilation in room temperature noble gases is simulated using accurate scattering and annihilation cross sections calculated with manybody theory, enabling the first simultaneous probing of the energy dependence of the scattering and annihilation cross sections. A strikingly small fraction of positrons is shown to survive to thermalization: ∼ 0.1 in He, ∼ 0 in Ne, ∼ 0.15 in Ar, ∼ 0.05 in Kr, and ∼ 0.01 in Xe. For Xe, the timevarying annihilation rate Z ¯ eff ( τ ) is shown to be highly sensitive to the depletion of the momentum distribution due to annihilation, conclusively explaining the longstanding discrepancy between gascell and trapbased measurements. Overall, the use of the accurate atomic data gives Z ¯ eff ( τ ) in close agreement with experiment for all noble gases except Ne, the experiment for which is proffered to have suffered from incomplete knowledge of the fraction of positrons surviving to thermalization and/or the presence of impurities.

GeigerNuttall Law for Nuclei in Strong Electromagnetic Fields Phys. Rev. Lett. (IF 8.462) Pub Date : 20171116
D. S. Delion and S. A. GhinescuWe investigate the influence of a strong laser electromagnetic field on the α decay rate by using the Hennenberger frame of reference. We introduce an adimensional parameter D = S 0 / R 0 , where R 0 is the geometrical nuclear radius and S 0 ∼ I / ω 2 is a length parameter depending on the laser intensity I and frequency ω . We show that the barrier penetrability has a strong increase for intensities corresponding to D > D crit = 1 , due to the fact that the resulting Coulomb potential becomes strongly anisotropic even for spherical nuclei. As a consequence, the contribution of the monopole term increases the barrier penetrability by 2 orders of magnitude, while the total contribution has an effect of 6 orders of magnitude at D ∼ 3 D crit . In the case of deformed nuclei, the electromagnetic field increases the penetrability by an additional order of magnitude for a quadrupole deformation β 2 ∼ 0.3 . The influence of the electromagnetic field can be expressed in terms of a shifted GeigerNuttal law by a term depending on S 0 and deformation.

DoubleCascade Events from New Physics in Icecube Phys. Rev. Lett. (IF 8.462) Pub Date : 20171116
Pilar Coloma, Pedro A. N. Machado, Ivan MartinezSoler, and Ian M. ShoemakerA variety of new physics models allows for neutrinos to upscatter into heavier states. If the incident neutrino is energetic enough, the heavy neutrino may travel some distance before decaying. In this work, we consider the atmospheric neutrino flux as a source of such events. At IceCube, this would lead to a “doublebang” (DB) event topology, similar to what is predicted to occur for tau neutrinos at ultrahigh energies. The DB event topology has an extremely low background rate from coincident atmospheric cascades, making this a distinctive signature of new physics. Our results indicate that IceCube should already be able to derive new competitive constraints on models with GeVscale sterile neutrinos using existing data.

Lorentz Symmetry Violations from MatterGravity Couplings with Lunar Laser Ranging Phys. Rev. Lett. (IF 8.462) Pub Date : 20171116
A. Bourgoin, C. Le PoncinLafitte, A. Hees, S. Bouquillon, G. Francou, and M.C. Angonin 
SuperconductingGravimeter Tests of Local Lorentz Invariance Phys. Rev. Lett. (IF 8.462) Pub Date : 20171116
Natasha A. Flowers, Casey Goodge, and Jay D. Tasson 
Digital Quantum Estimation Phys. Rev. Lett. (IF 8.462) Pub Date : 20171116
Majid Hassani, Chiara Macchiavello, and Lorenzo MacconeQuantum metrology calculates the ultimate precision of all estimation strategies, measuring what is their rootmeansquare error (RMSE) and their Fisher information. Here, instead, we ask how many bits of the parameter we can recover; namely, we derive an informationtheoretic quantum metrology. In this setting, we redefine “Heisenberg bound” and “standard quantum limit” (the usual benchmarks in the quantum estimation theory) and show that the former can be attained only by sequential strategies or parallel strategies that employ entanglement among probes, whereas parallelseparable strategies are limited by the latter. We highlight the differences between this setting and the RMSEbased one.

Interaction Dependent Heating and Atom Loss in a Periodically Driven Optical Lattice Phys. Rev. Lett. (IF 8.462) Pub Date : 20171116
Martin Reitter, Jakob Näger, Karen Wintersperger, Christoph Sträter, Immanuel Bloch, André Eckardt, and Ulrich Schneider 
Lattice Model to Derive the Fluctuating Hydrodynamics of Active Particles with Inertia Phys. Rev. Lett. (IF 8.462) Pub Date : 20171115
A. Manacorda and A. PuglisiWe derive the hydrodynamic equations with fluctuating currents for the density, momentum, and energy fields for an active system in the dilute limit. In our model, nonoverdamped selfpropelled particles (such as grains or birds) move on a lattice, interacting by means of aligning dissipative forces and excluded volume repulsion. Our macroscopic equations, in a specific case, reproduce a transition line from a disordered phase to a swarming phase and a linear dispersion law accounting for underdamped wave propagation. Numerical simulations up to a packing fraction ∼10% are in fair agreement with the theory, including the macroscopic noise amplitudes. At a higher packing fraction, a densediluted coexistence emerges. We underline the analogies with the granular kinetic theories, elucidating the relation between the active swarming phase and granular shear instability.

Flow of Deformable Droplets: Discontinuous Shear Thinning and Velocity Oscillations Phys. Rev. Lett. (IF 8.462) Pub Date : 20171115
M. Foglino, A. N. Morozov, O. Henrich, and D. MarenduzzoWe study the rheology of a suspension of soft deformable droplets subjected to a pressuredriven flow. Through computer simulations, we measure the apparent viscosity as a function of droplet concentration and pressure gradient, and provide evidence of a discontinuous shear thinning behavior, which occurs at a concentrationdependent value of the forcing. We further show that this response is associated with a nonequilibrium transition between a “hard” (or less deformable) phase, which is nearly jammed and flows very slowly, and a “soft” (or more deformable) phase, which flows much more easily. The soft phase is characterized by flowinduced time dependent shape deformations and internal currents, which are virtually absent in the hard phase. Close to the transition, we find sustained oscillations in both the droplet and fluid velocities. Polydisperse systems show similar phenomenology but with a smoother transition, and less regular oscillations.

Optimizing Hyperuniformity in SelfAssembled Bidisperse Emulsions Phys. Rev. Lett. (IF 8.462) Pub Date : 20171115
Joshua Ricouvier, Romain Pierrat, Rémi Carminati, Patrick Tabeling, and Pavel YazhgurWe study long range density fluctuations (hyperuniformity) in twodimensional jammed packings of bidisperse droplets. Taking advantage of microfluidics, we systematically span a large range of size and concentration ratios of the two droplet populations. We identify various defects increasing long range density fluctuations mainly due to organization of local particle environment. By choosing an appropriate bidispersity, we fabricate materials with a high level of hyperuniformity. Interesting transparency properties of these optimized materials are established based on numerical simulations.

Competition between Chaotic and Nonchaotic Phases in a Quadratically Coupled SachdevYeKitaev Model Phys. Rev. Lett. (IF 8.462) Pub Date : 20171115
Xin Chen, Ruihua Fan, Yiming Chen, Hui Zhai, and Pengfei ZhangThe SachdevYeKitaev (SYK) model is a concrete solvable model to study nonFermi liquid properties, holographic duality, and maximally chaotic behavior. In this work, we consider a generalization of the SYK model that contains two SYK models with a different number of Majorana modes coupled by quadratic terms. This model is also solvable, and the solution shows a zerotemperature quantum phase transition between two nonFermi liquid chaotic phases. This phase transition is driven by tuning the ratio of two mode numbers, and a nonchaotic Fermi liquid sits at the critical point with an equal number of modes. At a finite temperature, the Fermi liquid phase expands to a finite regime. More intriguingly, a different nonFermi liquid phase emerges at a finite temperature. We characterize the phase diagram in terms of the spectral function, the Lyapunov exponent, and the entropy. Our results illustrate a concrete example of the quantum phase transition and critical behavior between two nonFermi liquid phases.

Solvable SachdevYeKitaev Models in Higher Dimensions: From Diffusion to ManyBody Localization Phys. Rev. Lett. (IF 8.462) Pub Date : 20171115
ShaoKai Jian and Hong YaoMany aspects of manybody localization (MBL) transitions remain elusive so far. Here, we propose a higherdimensional generalization of the SachdevYeKitaev (SYK) model and show that it exhibits a MBL transition. The model on a bipartite lattice has N Majorana fermions with SYK interactions on each site of the A sublattice and M free Majorana fermions on each site of the B sublattice, where N and M are large and finite. For r≡M/N<rc=1, it describes a diffusive metal exhibiting maximal chaos. Remarkably, its diffusive constant D vanishes [D∝(rc−r)1/2] as r→rc, implying a dynamical transition to a MBL phase. It is further supported by numerical calculations of level statistics which changes from WignerDyson (r<rc) to Poisson (r>rc) distributions. Note that no subdiffusive phase intervenes between diffusive and MBL phases. Moreover, the critical exponent ν=0, violating the Harris criterion. Our higherdimensional SYK model may provide a promising arena to explore exotic MBL transitions.

Generating CarrierEnvelopePhase Stabilized FewCycle Pulses from a FreeElectron Laser Oscillator Phys. Rev. Lett. (IF 8.462) Pub Date : 20171115
Ryoichi Hajima and Ryoji NagaiWe propose a scheme to generate carrierenvelopephase (CEP) stabilized fewcycle optical pulses from a freeelectron laser oscillator. The CEP stabilization is realized by the continuous injection of CEPstabilized seed pulses from an external laser to the freeelectron laser oscillator whose cavity length is perfectly synchronized to the electron bunch repetition. Operated at a midinfrared wavelength, the proposed method is able to drive a photon source based on high harmonic generation (HHG) to explore the generation of isolated attosecond pulses at photon energies above 1 keV with a repetition of >10 MHz. The HHG photon source will open a door to fullscale experiments of attosecond xray pulses and push ultrafast laser science to the zeptosecond regime.

Different Time Scales in the Dissociation Dynamics of CoreExcitedCF4by Two Internal Clocks Phys. Rev. Lett. (IF 8.462) Pub Date : 20171115
H. Iwayama, C. Léonard, F. Le Quéré, S. Carniato, R. Guillemin, M. Simon, M. N. Piancastelli, and E. ShigemasaFragmentation processes following C 1s→lowest unoccupied molecular orbital core excitations in CF4 have been analyzed on the ground of the angular distribution of the CF3+ emitted fragments by means of Auger electronphotoion coincidences. Different time scales have been enlightened, which correspond to either ultrafast fragmentation, on the fewfemtosecond scale, where the molecule has no time to rotate and the fragments are emitted according to the maintained orientation of the coreexcited species, or dissociation after resonant Auger decay, where the molecule still keeps some memory of the excitation process before reassuming random orientation. Potential energy surfaces of the ground, coreexcited, and final states have been calculated at the ab initio level, which show the dissociative nature of the neutral excited state, leading to ultrafast dissociation, as well as the also dissociative nature of some of the final ionic states reached after resonant Auger decay, yielding the same fragments on a much longer time scale.

Comparison Study of StrongField Ionization of Molecules and Atoms by Bicircular TwoColor Femtosecond Laser Pulses Phys. Rev. Lett. (IF 8.462) Pub Date : 20171115
Kang Lin, Xinyan Jia, Zuqing Yu, Feng He, Junyang Ma, Hui Li, Xiaochun Gong, Qiying Song, Qinying Ji, Wenbin Zhang, Hanxiao Li, Peifen Lu, Heping Zeng, Jing Chen, and Jian WuWe experimentally investigate the single and double ionization of N2 and O2 molecules in bicircular twocolor femtosecond laser pulses, and compare with their companion atoms of Ar and Xe with comparable ionization thresholds. Electron recollision assisted enhanced ionization is observed in N2 and Ar by controlling the helicity and field ratio between the two colors, whereas the enhanced ionization via the recollision is almost absent in O2 and Xe. Our Smatrix simulations clearly reveal the crucial role of the detailed electronic structures of N2 and O2 on the twodimensional recollision of the electrons driven by the bicircular twocolor laser fields. As compared to Ar, the resonant multiphoton excitation dominates the double ionization of Xe.

Signatures of Electronic Structure in Bicircular HighHarmonic Spectroscopy Phys. Rev. Lett. (IF 8.462) Pub Date : 20171115
Denitsa Baykusheva, Simon Brennecke, Manfred Lein, and Hans Jakob WörnerHighharmonic spectroscopy driven by circularly polarized laser pulses and their counterrotating second harmonic is a new branch of attosecond science which currently lacks quantitative interpretations. We extend this technique to the midinfrared regime and record detailed highharmonic spectra of several raregas atoms. These results are compared with the solution of the Schrödinger equation in three dimensions and calculations based on the strongfield approximation that incorporate accurate scatteringwave recombination matrix elements. A quantumorbit analysis of these results provides a transparent interpretation of the measured intensity ratios of symmetryallowed neighboring harmonics in terms of (i) a set of propensity rules related to the angular momentum of the atomic orbitals, (ii) atomspecific matrix elements related to their electronic structure, and (iii) the interference of the emissions associated with electrons in orbitals corotating or counterrotating with the laser fields. These results provide the foundation for a quantitative understanding of bicircular highharmonic spectroscopy.

First Exclusive Measurement of Deeply Virtual Compton Scattering offHe4: Toward the 3D Tomography of Nuclei Phys. Rev. Lett. (IF 8.462) Pub Date : 20171115
M. Hattawyet al.(CLAS Collaboration)We report on the first measurement of the beamspin asymmetry in the exclusive process of coherent deeply virtual Compton scattering off a nucleus. The experiment uses the 6 GeV electron beam from the Continuous Electron Beam Accelerator Facility (CEBAF) accelerator at Jefferson Lab incident on a pressurized He4 gaseous target placed in front of the CEBAF Large Acceptance Spectrometer (CLAS). The scattered electron is detected by CLAS and the photon by a dedicated electromagnetic calorimeter at forward angles. To ensure the exclusivity of the process, a specially designed radial time projection chamber is used to detect the recoiling He4 nuclei. We measure beamspin asymmetries larger than those observed on the free proton in the same kinematic domain. From these, we are able to extract, in a modelindependent way, the real and imaginary parts of the only He4 Compton form factor, HA. This first measurement of coherent deeply virtual Compton scattering on the He4 nucleus, with a fully exclusive final state via nuclear recoil tagging, leads the way toward 3D imaging of the partonic structure of nuclei.

HeavyQuark Symmetry Implies Stable Heavy Tetraquark MesonsQiQjq¯kq¯l Phys. Rev. Lett. (IF 8.462) Pub Date : 20171115
Estia J. Eichten and Chris Quigg 
Discovery of the Doubly CharmedΞccBaryon Implies a Stablebbu¯d¯Tetraquark Phys. Rev. Lett. (IF 8.462) Pub Date : 20171115
Marek Karliner and Jonathan L. Rosner
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