This report synthesizes ten foundational and contemporary works on crystalline and periodic structures in phase space as substrates for algorithmic computation and error-resilient dynamics. The review spans phase-space lattices in bosonic quantum codes (GKP), rotationally symmetric codes, driven Floquet systems, discrete time crystals, and the invariant manifolds of classical Hamiltonian dynamics. By analyzing the stabilizing mechanisms—symplectic invariants, modular variables, Many-Body Localization, and topological band structures—the document demonstrates how discrete symmetry breaking in position–momentum space and temporal domains yields robust, noise-resistant computational subspaces. The work bridges quantum information, nonlinear dynamics, and topological phases, establishing phase-space geometry as a primary resource for next-generation quantum and classical computational architectures.
This report synthesizes ten foundational and contemporary works on crystalline and periodic structures in phase space as substrates for algorithmic computation and error-resilient dynamics. The review spans phase-space lattices in bosonic quantum codes (GKP), rotationally symmetric codes, driven Floquet systems, discrete time crystals, and the invariant manifolds of classical Hamiltonian dynamics. By analyzing the stabilizing mechanisms—symplectic invariants, modular variables, Many-Body Localization, and topological band structures—the document demonstrates how discrete symmetry breaking in position–momentum space and temporal domains yields robust, noise-resistant computational subspaces. The work bridges quantum information, nonlinear dynamics, and topological phases, establishing phase-space geometry as a primary resource for next-generation quantum and classical computational architectures.
Time crystals are physical systems whose time translation symmetry is spontaneously broken. Although the spontaneous breaking of continuous time-translation symmetry in static systems is proved impossible for the equilibrium state, the discrete time-translation symmetry in periodically driven (Floquet) systems is allowed to be spontaneously broken, resulting in the so-called Floquet or discrete time crystals. While most works so far searching for time crystals focus on the symmetry breaking process and the possible stabilising mechanisms, the many-body physics from the interplay of symmetry-broken states, which we call the condensed matter physics in time crystals, is not fully explored yet. This review aims to summarise the very preliminary results in this new research field with an analogous structure of condensed matter theory in solids. The whole theory is built on a hidden symmetry in time crystals, i.e., the phase space lattice symmetry, which allows us to develop the band theory, topology and strongly correlated models in phase space lattice. In the end, we outline the possible topics and directions for the future research.
This book aims to develop a general framework of condensed matter theory in phase space, instead of configuration space, of a dynamical system. Different from Euclidean real space, phase space is embedded with symplectic geometry in classical mechanics or noncommutative geometry in quantum mechanics. Arbitrary lattice Hamiltonians and crystalline many-body states in phase space can be created with the Floquet approach. The book covers topics ranging from dynamical systems, Floquet theory, topological physics to quantum many-body physics and time crystals. The book fills in the blanks in the study of dynamical systems by considering many-body physics in the phase space. Key features • First book on phase space crystals • Covers both the basics and up-to-date research of condensed matter in dynamical systems • Contains systematic and comprehensive content for beginners • Relevant to multiple physics communities including quantum physics and nonlinear science.
Abstract Time crystals are physical systems whose time translation symmetry is spontaneously broken. Although the spontaneous breaking of continuous time-translation symmetry in static systems is proved impossible for the equilibrium state, the discrete time-translation symmetry in periodically driven (Floquet) systems is allowed to be spontaneously broken, resulting in the so-called Floquet or discrete time crystals. While most works so far searching for time crystals focus on the symmetry breaking process and the possible stabilising mechanisms, the many-body physics from the interplay of symmetry-broken states, which we call the condensed matter physics in time crystals, is not fully explored yet. This review aims to summarise the very preliminary results in this new research field with an analogous structure of condensed matter theory in solids. The whole theory is built on a hidden symmetry in time crystals, i.e., the phase space lattice symmetry, which allows us to develop the band theory, topology and strongly correlated models in phase space lattice. In the end, we outline the possible topics and directions for the future research.
The simulation of non-equilibrium quantum many-body systems on noisy intermediate-scale quantum (NISQ) processors represents a central challenge and opportunity in modern condensed matter physics. Periodically driven (Floquet) systems can host exotic phases of matter with no equilibrium counterpart, most notably discrete time crystals (DTCs) characterized by spontaneous breaking of discrete time-translation symmetry and robust subharmonic responses. However, the realization of DTCs faces fundamental obstacles: driven many-body systems generically absorb energy and thermalize to an infinite-temperature state, destroying time-crystalline order. Two primary mechanisms have been identified to stabilize DTCs—many-body localization (MBL) through strong disorder, and Floquet prethermalization wherein high-frequency driving suppresses heating over exponentially long timescales. This work investigates the digital quantum simulation of prethermal DTCs on current superconducting quantum processors, with a focus on understanding and mitigating the impact of hardware noise. Recent experiments on 133-qubit heavy-hexagonal devices have demonstrated the realization of clean two-dimensional DTCs and incommensurately modulated DTCs (IM-DTCs) using kicked Ising models, observing period-doubling oscillations persisting for up to 100 Floquet cycles . Crucially, these simulations reveal that quantum noise, often perceived as detrimental, can in certain regimes stabilize novel prethermal DTC phases—a phenomenon identified as noise-induced DTCs supported by symmetry charge pumping or random gate fluctuations . The heavy-hexagonal lattice geometry, compared to square lattices, exhibits significantly slower quantum scrambling, thereby extending the prethermal plateau and enhancing DTC stability. We address two key challenges limiting the scalability of DTC simulations: limited qubit connectivity and environmental noise. By leveraging the universality of native gate sets, we demonstrate how to implement effective couplings among physically disconnected qubits at the cost of increased circuit depth, enabling the study of interaction-range effects on DTC stabilization—a phenomenon previously unobserved experimentally . Furthermore, we benchmark the performance of error mitigation protocols based on depolarising noise models, achieving excellent agreement between error-mitigated hardware data and tensor-network simulations in regimes where classical computations remain tractable . Our results highlight the complementary roles of quantum hardware and classical simulation: quantum processors provide access to regimes where entanglement growth outpaces tensor-network methods, while careful validation against classical benchmarks ensures the reliability of quantum outcomes. This study establishes a concrete pathway for using NISQ devices as experimental platforms for synthesizing and probing novel non-equilibrium quantum phases, advancing both our fundamental understanding of Floquet many-body dynamics and the practical capabilities of quantum simulation. The identification of noise as an active ingredient in phase stabilization suggests new directions for quantum engineering of spatiotemporal orders on near-term hardware.
Time crystals are nonequilibrium phases of matter characterized by the emergence of temporal ordering, in which an interacting many-body system develops robust structure in its time evolution that is not trivially dictated by the external driving or environment. While related phenomena have long been studied in classical nonlinear systems, their realization in entangled quantum matter represents a distinct frontier. The theoretical understanding of discrete time crystals has substantially advanced, yet recent experiments using modern quantum devices and quantum processors reveal regimes beyond established paradigms. These developments call for an extended classification of time-crystalline phases according to both their stabilization mechanisms and their physical character, including discrete and continuous, closed and open, critical, topological, quasiperiodic, and controlled realizations. We review recent implementations of time crystals on quantum platforms and propose such a classification framework, identifying promising directions for the discovery of novel time-crystalline phases of matter.
Discrete Time Crystals (DTCs) are a non-equilibrium phase of matter that breaks the time-translation symmetry. This manifests as robust oscillations observed in driven Hamiltonians. Realizing DTCs on current Noisy Intermediate-Scale Quantum (NISQ) computers can be challenging due to the environmental noise, decoherence of qubits and computational errors. This thesis investigates the resilience and robustness of DTC and examines recent developments, and possible improvements of DTC stabilization using current quantum processors. Generally, an externally driven many-body system is expected to heat up to an infinite temperature state. This process, which is called thermalization, prevents the time-crystalline order. The two primary mechanisms that protect time-crystalline order are many-body localization (MBL) which has a strong disorder that prevents the thermalization, and Floquet prethermalization where its high frequency driving prevents the thermalization. These two processes allow us to realize and investigate the time crystals before a quantum system thermalizes.