Quantum many-body systems subjected to unitary evolution with the addition of interspersed measurements exhibit a variety of dynamical phases that do not occur under pure unitary evolution. However, these systems remain challenging to investigate on near-term quantum hardware owing to the need for numerous ancilla qubits or repeated high-fidelity mid-circuit measurements, a capability that has only recently become available. Here we report the realization of a measurement-induced entanglement phase transition with a hybrid random circuit on up to 14 superconducting qubits with mid-circuit readout capability. We directly observe extensive and sub-extensive scaling of entanglement entropy in the volume- and area-law phases, respectively, by varying the rate of the measurements. We also demonstrate phenomenological critical behaviour by performing a data collapse of the measured entanglement entropy. Our work establishes the use of mid-circuit measurement as a powerful resource for quantum simulation on near-term quantum computers.

经历酉演化并添加散布测量的量子多体系统表现出在纯酉演化下不会出现的各种动力学阶段。然而，由于需要大量的辅助量子位或重复的高保真中电路测量，这些系统在近期的量子硬件上的研究仍然具有挑战性，这种能力最近才可用。在这里，我们报告了在多达 14 个具有中间电路读出能力的超导量子位上使用混合随机电路实现测量引起的纠缠相变。通过改变测量速率，我们分别在体积定律和面积定律阶段直接观察到纠缠熵的广泛和次广泛缩放。我们还通过执行测量的纠缠熵的数据崩溃来证明现象学的临界行为。我们的工作确立了使用中路测量作为近期量子计算机上量子模拟的强大资源。