We study dynamical signatures of quantum chaos in one of the most relevant models in many-body quantum mechanics, the Bose-Hubbard model, whose high degree of symmetries yields a large number of invariant subspaces and degenerate energy levels. The standard procedure to reveal signatures of quantum chaos requires classifying the energy levels according to their symmetries, which may be experimentally and theoretically challenging. We show that this classification is not necessary to observe manifestations of spectral correlations in the temporal evolution of the survival probability, which makes this quantity a powerful tool in the identification of chaotic many-body quantum systems.
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http://dx.doi.org/10.1103/PhysRevE.102.032208 | DOI Listing |
Entropy (Basel)
January 2025
Department of Physics and Fujian Provincial Key Laboratory of Low Dimensional Condensed Matter Physics, Xiamen University, Xiamen 361005, China.
We show that the theory of quantum statistical mechanics is a special model in the framework of the quantum probability theory developed by mathematicians, by extending the characteristic function in the classical probability theory to the quantum probability theory. As dynamical variables of a quantum system must respect certain commutation relations, we take the group generated by a Lie algebra constructed with these commutation relations as the bridge, so that the classical characteristic function defined in a Euclidean space is transformed to a normalized, non-negative definite function defined in this group. Indeed, on the quantum side, this group-theoretical characteristic function is equivalent to the density matrix; hence, it can be adopted to represent the state of a quantum ensemble.
View Article and Find Full Text PDFRep Prog Phys
January 2025
SISSA, via Bonomea 265, 34136 Trieste, Trieste, 34136, ITALY.
We review recent progress regarding the double scaled Sachdev-Ye-Kitaev model and other p-local quantum mechanical random Hamiltonians. These models exhibit an expansion using chord diagrams, which can be solved by combinatorial methods. We describe exact results in these models, including their spectrum, correlation functions, and Lyapunov exponent.
View Article and Find Full Text PDFChaos
January 2025
School of Mechanical and Power Engineering, Zhengzhou University, Science Road 100, 450001 Zhengzhou, China.
In this paper, the complex and dynamically rich distribution of stable phases in the well-known discrete Ikeda map is studied in detail. The unfolding patterns of these stable phases are described through three complementary stability diagrams: the Lyapunov stability diagram, the isoperiod stability diagram, and the isospike stability diagram. The adding-doubling complexification cascade and fascinating non-quantum chiral pairs are discovered, marking the first report of such structures in discrete mapping.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Freie Universität Berlin, Department of Mathematics and Computer Science, Arnimallee 6, 14195 Berlin, Germany.
Quantum batteries are energy-storing devices, governed by quantum mechanics, that promise high charging performance thanks to collective effects. Because of its experimental feasibility, the Dicke battery-which comprises N two-level systems coupled to a common photon mode-is one of the most promising designs for quantum batteries. However, the chaotic nature of the model severely hinders the extractable energy (ergotropy).
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Instituto de Investigaciones en Matemáticas Aplicadas y en Sistemas, Universidad Nacional Autónoma de México, C.P. 04510 Mexico City, Mexico.
Quantum chaos has recently received increasing attention due to its relationship with experimental and theoretical studies of nonequilibrium quantum dynamics, thermalization, and the scrambling of quantum information. In an isolated system, quantum chaos refers to properties of the spectrum that emerge when the classical counterpart of the system is chaotic. However, despite experimental progress leading to longer coherence times, interactions with an environment can never be neglected, which calls for a definition of quantum chaos in dissipative systems.
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