Abstract
An equiangular tight frame (ETF) is a sequence of vectors in a Hilbert space that achieves equality in the Welch bound and so has minimal coherence. More generally, an equichordal tight fusion frame (ECTFF) is a sequence of equi-dimensional subspaces of a Hilbert space that achieves equality in Conway, Hardin and Sloane’s simplex bound. Every ECTFF is a type of optimal Grassmannian code, that is, an optimal packing of equi-dimensional subspaces of a Hilbert space. We construct ECTFFs by exploiting new relationships between known ETFs. Harmonic ETFs equate to difference sets for finite abelian groups. We say that a difference set for such a group is “paired” with a difference set for its Pontryagin dual when the corresponding subsequence of its harmonic ETF happens to be an ETF for its span. We show that every such pair yields an ECTFF. We moreover construct an infinite family of paired difference sets using quadratic forms over the field of two elements. Together this yields two infinite families of real ECTFFs.
Similar content being viewed by others
References
Appleby M., Bengtsson I., Dumitru I., Flammia S.: Dimension towers of SICs. I. Aligned SICs and embedded tight frames. J. Math. Phys. 58, 112201 (2017).
Bachoc C., Ehler M.: Tight \(p\)-fusion frames. Appl. Comput. Harmon. Anal. 35, 1–15 (2013).
Bachoc C., Bannai E., Coulangeon R.: Codes and designs in Grassmannian spaces. Discret. Math. 277, 15–28 (2004).
Bajwa W.U., Calderbank R., Mixon D.G.: Two are better than one: fundamental parameters of frame coherence. Appl. Comput. Harmon. Anal. 33, 58–78 (2012).
Bandeira A.S., Fickus M., Mixon D.G., Wong P.: The road to deterministic matrices with the Restricted Isometry Property. J. Fourier Anal. Appl. 19, 1123–1149 (2013).
Barg A., Glazyrin A., Okoudjou K.A., Yu W.-H.: Finite two-distance tight frames. Linear Algebra Appl. 475, 163–175 (2015).
Blokhuis A., Brehm U., Et-Taoui B.: Complex conference matrices and equi-isoclinic planes in Euclidean spaces. Beitr. Algebra Geom. 59, 491–500 (2018).
Bodmann B.G.: Optimal linear transmission by loss-insensitive packet encoding. Appl. Comput. Harmon. Anal. 22, 274–285 (2007).
Bodmann B.G., Elwood H.J.: Complex equiangular Parseval frames and Seidel matrices containing \(p\)th roots of unity. Proc. Am. Math. Soc. 138, 4387–4404 (2010).
Bodmann B., King E.J.: Optimal arrangements of classical and quantum states with limited purity. J. Lond. Math. Soc. 101, 393–431 (2020).
Brouwer A.E.: Strongly regular graphs. In: Colbourn C.J., Dinitz J.H. (eds.) Handbook of Combinatorial Designs, 2nd edn., pp. 852–868 (2007).
Brouwer A.E.: Parameters of strongly regular graphs. http://www.win.tue.nl/~aeb/graphs/srg/srgtab.html
Calderbank A.R., Cameron P.J., Kantor W.M., Seidel J.J.: \({\mathbb{Z}}_4\)-Kerdock codes, orthogonal spreads, and extremal Euclidean line-sets. Proc. Lond. Math. Soc. 75, 436–480 (1997).
Calderbank A.R., Hardin R.H., Rains E.M., Shor P.W., Sloane N.J.A.: A group-theoretic framework for the construction of packings in Grassmannian spaces. J. Algebr. Combin. 9, 129–140 (1999).
Calderbank R., Thompson A., Xie Y.: On block coherence of frames. Appl. Comput. Harmon. Anal. 38, 50–71 (2015).
Cameron P.J., Seidel J.J.: Quadratic forms over \(GF(2)\). Indag. Math. 76, 1–8 (1973).
Casazza P.G., Fickus M., Mixon D.G., Wang Y., Zhou Z.: Constructing tight fusion frames. Appl. Comput. Harmon. Anal. 30, 175–187 (2011).
Cohn H., Kumar A., Minton G.: Optimal simplices and codes in projective spaces. Geom. Topol. 20, 1289–1357 (2016).
Conway J.H., Hardin R.H., Sloane N.J.A.: Packing lines, planes, etc.: packings in Grassmannian spaces. Exp. Math. 5, 139–159 (1996).
Coutinho G., Godsil C., Shirazi H., Zhan H.: Equiangular lines and covers of the complete graph. Linear Algebra Appl. 488, 264–283 (2016).
Creignou J.: Constructions of Grassmannian simplices (2008). arXiv:cs/0703036.
Dhillon I.S., Heath J.R., Strohmer T., Tropp J.A.: Constructing packings in Grassmannian manifolds via alternating projection. Exp. Math. 17, 9–35 (2008).
Ding C., Feng T.: A generic construction of complex codebooks meeting the Welch bound. IEEE Trans. Inform. Theory 53, 4245–4250 (2007).
Eldar Y.C., Kuppinger P., Bölcskei H.: Block-sparse signals: uncertainty relations and efficient recovery IEEE Trans. Signal Process. 58, 3042–3054 (2010).
Et-Taoui B.: Infinite family of equi-isoclinic planes in Euclidean odd dimensional spaces and of complex symmetric conference matrices of odd orders. Linear Algebra Appl. 556, 373–380 (2018).
Et-Taoui B.: Quaternionic equiangular lines. Adv. Geom. 20, 273–284 (2020).
Fickus M.: Maximally equiangular frames and Gauss sums. J. Fourier Anal. Appl. 15, 413–427 (2009).
Fickus M., Mixon D.G.: Tables of the existence of equiangular tight frames (2016). arXiv:1504.00253.
Fickus M., Schmitt C.A.: Harmonic equiangular tight frames comprised of regular simplices. Linear Algebra Appl. 586, 130–169 (2020).
Fickus M., Mixon D.G., Tremain J.C.: Steiner equiangular tight frames. Linear Algebra Appl. 436, 1014–1027 (2012).
Fickus M., Mixon D.G., Jasper J.: Equiangular tight frames from hyperovals. IEEE Trans. Inform. Theory. 62, 5225–5236 (2016).
Fickus M., Jasper J., King E.J., Mixon D.G.: Equiangular tight frames that contain regular simplices. Linear Algebra Appl. 555, 98–138 (2018).
Fickus M., Jasper J., Mixon D.G., Peterson J.D.: Tremain equiangular tight frames. J. Combin. Theory Ser. A 153, 54–66 (2018).
Fickus M., Jasper J., Mixon D.G., Peterson J.D., Watson C.E.: Equiangular tight frames with centroidal symmetry. Appl. Comput. Harmon. Anal. 44, 476–496 (2018).
Fickus M., Jasper J., Mixon D.G., Peterson J.D., Watson C.E.: Polyphase equiangular tight frames and abelian generalized quadrangles. Appl. Comput. Harmon. Anal. 47, 628–661 (2019).
Fickus M., Mayo B.R., Watson C.E.: Certifying the novelty of equichordal tight fusion frames (2021). arXiv:2103.03192.
Fuchs C.A., Hoang M.C., Stacey B.C.: The SIC question: history and state of play. Axioms 6(21), 1–20 (2017).
Goethals J.M., Seidel J.J.: Strongly regular graphs derived from combinatorial designs. Can. J. Math. 22, 597–614 (1970).
Gordon D.: Difference sets. https://www.dmgordon.org/diffset/.
Grove L.C.: In: Grad. Stud. Math. 39, Amer. Math. Soc., (ed.) Classical groups and geometric algebra. (2002).
Hoggar S.G.: New sets of equi-isoclinic \(n\)-planes from old. Proc. Edinb. Math. Soc. 20, 287–291 (1977).
Holmes R.B., Paulsen V.I.: Optimal frames for erasures. Linear Algebra Appl. 377, 31–51 (2004).
Iverson J.W., Mixon D.G.: Doubly transitive lines I. Higman pairs and roux. arXiv:1806.09037.
Iverson J.W., Jasper J., Mixon D.G.: Optimal line packings from finite group actions. Forum Math. Sigma 8, 1–40 (2020).
Jasper J., Mixon D.G., Fickus M.: Kirkman equiangular tight frames and codes. IEEE Trans. Inform. Theory. 60, 170–181 (2014).
Jungnickel D., Pott A., Smith K.W.: Difference sets, in: C.J. Colbourn, J.H. Dinitz (eds.) CRC Handbook of Combinatorial Designs, pp. 419–435 (2007).
King E.J.: New constructions and characterizations of flat and almost flat Grassmannian fusion frames (2016). arXiv:1612.05784.
King E.J.: Creating subspace packings from other subspace packings. Linear Algebra Appl. 625, 68–80 (2021).
Kocák T., Niepel M.: Families of optimal packings in real and complex Grassmannian spaces. J. Algebr. Combin. 45, 129–148 (2017).
König H.: Cubature formulas on spheres. Math. Res. 107, 201–212 (1999).
Kutyniok G., Pezeshki A., Calderbank R., Liu T.: Robust dimension reduction, fusion frames, and Grassmannian packings. Appl. Comput. Harmon. Anal. 26, 64–76 (2009).
Lemmens P.W.H., Seidel J.J.: Equi-isoclinic subspaces of Euclidean spaces. Indag. Math. 76, 98–107 (1973).
Renes J.M., Blume-Kohout R., Scott A.J., Caves C.M.: Symmetric informationally complete quantum measurements. J. Math. Phys. 45, 2171–2180 (2004).
Strohmer T., Heath R.W.: Grassmannian frames with applications to coding and communication. Appl. Comput. Harmon. Anal. 14, 257–275 (2003).
Taylor D.E.: The Geometry of the Classical Groups. Sigma Series in Pure Mathematics 9. Heldermann Verlag (1992).
Turyn R.J.: Character sums and difference sets. Pac. J. Math. 15, 319–346 (1965).
Waldron S.: On the construction of equiangular frames from graphs. Linear Algebra Appl. 431, 2228–2242 (2009).
Waldron S.: Tight frames over the quaternions and equiangular lines. arXiv:2006.06126.
Welch L.R.: Lower bounds on the maximum cross correlation of signals. IEEE Trans. Inform. Theory 20, 397–399 (1974).
Xia P., Zhou S., Giannakis G.B.: Achieving the Welch bound with difference sets. IEEE Trans. Inform. Theory 51, 1900–1907 (2005).
Zauner G.: Quantum Designs: Foundations of a Noncommutative Design Theory. Ph.D. Thesis, University of Vienna (1999).
Zhang T., Ge G.: Combinatorial constructions of packings in Grassmannian spaces. Des. Codes Cryptogr. 86, 803–815 (2018).
Acknowledgements
The authors thank Prof. Dustin G. Mixon and the two anonymous reviewers for their thoughtful comments. We are especially grateful for the anonymous remark that led to Theorem 3.6. This work was partially supported by NSF DMS 1830066, and began during the Summer of Frame Theory (SOFT) 2016. The views expressed in this article are those of the authors and do not reflect the official policy or position of the United States Air Force, Department of Defense, or the U.S. Government.
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by K.-U. Schmidt.
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Fickus, M., Iverson, J.W., Jasper, J. et al. Grassmannian codes from paired difference sets. Des. Codes Cryptogr. 89, 2553–2576 (2021). https://doi.org/10.1007/s10623-021-00937-w
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10623-021-00937-w