We show that the emergence of a ``magic barrier'', characterized by a transient maximum of nonstabilizerness during rapid entanglement growth, is a universal feature of thermalization within quantum ergodic theories, which is intimately connected to random matrix spectral properties. Starting from a pure product state, we analytically determine the time evolution of entanglement entropy, antiflatness, capacity of entanglement, and nonlocal trace distance magic under unitary dynamics generated by random matrix Hamiltonians drawn from all three Gaussian ensembles. We find that the transient maxima of antiflatness, capacity of entanglement, and nonlocal magic occur on the same characteristic timescale as the maximum rate of entanglement growth. These results establish that the magic barrier is a universal feature of RMT thermalization, suggesting universality across quantum chaotic systems. We conclude that quantitative simulations of thermalization in ergodic quantum theories inherently require quantum computation.We show that the emergence of a ``magic barrier'', characterized by a transient maximum of nonstabilizerness during rapid entanglement growth, is a universal feature of thermalization within quantum ergodic theories, which is intimately connected to random matrix spectral properties. Starting from a pure product state, we analytically determine the time evolution of entanglement entropy, antiflatness, capacity of entanglement, and nonlocal trace distance magic under unitary dynamics generated by random matrix Hamiltonians drawn from all three Gaussian ensembles. We find that the transient maxima of antiflatness, capacity of entanglement, and nonlocal magic occur on the same characteristic timescale as the maximum rate of entanglement growth. These results establish that the magic barrier is a universal feature of RMT thermalization, suggesting universality across quantum chaotic systems. We conclude that quantitative simulations of thermalization in ergodic quantum theories inherently require quantum computation.

hep-thCross-listedarXiv:2610.20768Oct 16, 20260 citations

RANDOM MATRIX FORMULATIONS TOWARD QUANTUM INFORMATION THEORY

洋長谷川, 利也高見

数理解析研究所講究録Mar 1, 19940 citations

Tensor product random matrix theory

Alexander Altland, Joaquim Telles de Miranda, Tobias Micklitz

The evolution of complex correlated quantum systems such as random circuit networks is governed by the dynamical buildup of both entanglement and entropy. We here introduce a real-time field theory approach—essentially a fusion of the G Σ functional of the SYK model and the field theory of disordered systems—engineered to microscopically describe the full range of such crossover dynamics: from initial product states to a maximum entropy ergodic state. To showcase this approach in the simplest nontrivial setting, we consider a tensor product of coupled random matrices, and compare to exact diagonalization. Published by the American Physical Society 2024The evolution of complex correlated quantum systems such as random circuit networks is governed by the dynamical buildup of both entanglement and entropy. We here introduce a real-time field theory approach—essentially a fusion of the G Σ functional of the SYK model and the field theory of disordered systems—engineered to microscopically describe the full range of such crossover dynamics: from initial product states to a maximum entropy ergodic state. To showcase this approach in the simplest nontrivial setting, we consider a tensor product of coupled random matrices, and compare to exact diagonalization. Published by the American Physical Society 2024

arXiv:2404.10919Physical Review ResearchOct 30, 20244 citations

RANDOM MATRIX FORMULATIONS TOWARD QUANTUM INFORMATION THEORY

Hiroshi Hasegawa, Toshiya Takami

数理解析研究所講究録Mar 1, 19940 citations

On the spectral gap of random quantum channels

Carlos E. González-Guillén, Marius Junge, Ion Nechita

In this work, we prove a lower bound on the difference between the first and second singular values of quantum channels induced by random isometries, that is tight in the scaling of the number of Kraus operators. This allows us to give an upper bound on the difference between the first and second largest (in modulus) eigenvalues of random channels with same large input and output dimensions for finite number of Kraus operators $k\geq 169$ . Moreover, we show that these random quantum channels are quantum expanders, answering a question posed by Hastings. As an application, we show that ground states of infinite 1D spin chains, which are well-approximated by matrix product states, fulfill a principle of maximum entropy.In this work, we prove a lower bound on the difference between the first and second singular values of quantum channels induced by random isometries, that is tight in the scaling of the number of Kraus operators. This allows us to give an upper bound on the difference between the first and second largest (in modulus) eigenvalues of random channels with same large input and output dimensions for finite number of Kraus operators $k\geq 169$. Moreover, we show that these random quantum channels are quantum expanders, answering a question posed by Hastings. As an application, we show that ground states of infinite 1D spin chains, which are well-approximated by matrix product states, fulfill a principle of maximum entropy.

arXiv:1811.08847Nov 21, 20186 citations

k\geq 169

. Moreover, we show that these random quantum channels are quantum expanders, answering a question posed by Hastings. As an application, we show that ground states of infinite 1D spin chains, which are well-approximated by matrix product states, fulfill a principle of maximum entropy.