Traditional condensed matter physics views quantum phase transitions as critical phenomena occurring strictly at specific critical coupling parameters, where correlation lengths diverge and critical fluctuations emerge locally or globally. In this work, we propose the paradigm of Quantum Critical Precognition (QCP), suggesting that quantum many-body systems can encode signatures of future critical structures prior to actual parameter tuning into the critical regime. By defining a novel information-theoretic metric, the Precognition Index Pi(t) based on mutual information between current states X(t) and future states X(t + Delta t), we formalize how non-local quantum entanglement and advanced temporal correlations act as precursors to phase transitions. We establish the theoretical foundation, dynamical evolution equations, and thermodynamic constraints of QCP, demonstrating that anticipation is a natural consequence of quantum coherence and informational pathways in closed and open quantum systems.
Traditional condensed matter physics views quantum phase transitions as critical phenomena occurring strictly at specific critical coupling parameters, where correlation lengths diverge and critical fluctuations emerge locally or globally. In this work, we propose the paradigm of Quantum Critical Precognition (QCP), suggesting that quantum many-body systems can encode signatures of future critical structures prior to actual parameter tuning into the critical regime. By defining a novel information-theoretic metric, the Precognition Index Pi(t) based on mutual information between current states X(t) and future states X(t + Delta t), we formalize how non-local quantum entanglement and advanced temporal correlations act as precursors to phase transitions. We establish the theoretical foundation, dynamical evolution equations, and thermodynamic constraints of QCP, demonstrating that anticipation is a natural consequence of quantum coherence and informational pathways in closed and open quantum systems.
Quantum materials exhibit rich phenomenology when driven across quantum critical points. Conventional quantum phase transitions are characterized by the change of an order parameter and the emergence of a divergent correlation length. In this work we propose a new class of quantum phase transitions, termed Quantum Matter Causal Phase Transitions (QMCPT), where the underlying causal structure of the many‑body wavefunction reorganizes itself rather than merely the order parameter. We develop a theoretical framework that describes how a causal graph, built from the entanglement structure of the ground state, can undergo a topological change. The transition is marked by a discontinuity or singularity in the causal depth, a quantity that counts the minimal number of layers of local operations required to prepare the state from a product state. We derive scaling relations for the causal depth near criticality, establish its universal behaviour, and discuss possible experimental signatures in strongly correlated systems such as heavy‑fermion compounds and twisted bilayer graphene. The QMCPT framework offers a new classification of quantum phases and provides a bridge between quantum information theory and condensed matter physics, opening pathways for identifying new materials with quantum critical behaviour and potential Nobel‑level discoveries.
This paper presents a formal framework framing quantum decoherence as an information-theoretic phase transition at the quantum-to-classical boundary. We demonstrate that environment-induced superselection (einselection) can be characterized as a true dynamical phase transition where the system-environment coupling strength acts as a thermodynamic control parameter, and the suppression of off-diagonal density matrix elements functions as an order parameter analogous to magnetization in the Ising model. Using quantum mutual information, von Neumann entropy, and entanglement entropy, we track the operational flow of information from a quantum system into environmental degrees of freedom, demonstrating how a singular classical reality emerges via the redundant copying of pointer states into environmental fragments—a process governed by Quantum Darwinism. We analyze a simulated spin-boson model and random unitary circuits with tunable dissipation, extracting clear signatures of criticality including power-law scaling and diverging correlation times at a critical threshold . Crucially, we connect this behavior to recent advancements (2023–2025) in mixed-state topological order, establishing that decoherence-induced transitions map onto anyon condensation transitions within an errorfield double formulation. Finally, we explore the foundational implications of this framework: it sharpens the measurement problem via informational symmetry breaking, reframes observation as a high-decoherence thermodynamic limit, and introduces a Gödelian perspective by demonstrating that determining the critical threshold for arbitrary many-body environments is formally undecidable due to the non-computability of the spectral gap in the thermodynamic limit.
Out-of-equilibrium quantum many-body systems stand at the forefront of modern theoretical physics, addressing fundamental questions on thermalization, transport, and universal phenomena. These fields, already well established in condensed matter, statistical physics, quantum optics, and quantum information theory, are progressively gaining even greater relevance with the rapid development of quantum technologies and simulation, which inherently operate in dynamical regimes. In recent years, the traditional paradigm of unitary quantum evolution has been expanded to include measurements, opening new directions in out-of-equilibrium physics. At the core of these advances lie measurement-induced phase transitions (MIPTs), which have emerged as a new class of dynamical critical phenomena characterizing the general behavior of monitored quantum dynamics. When external monitoring intertwines with unitary evolution, many-body quantum correlations change their structure, giving rise to distinct entanglement phases of matter. This discovery has sparked enormous interest in MIPTs, leading to significant advances in open quantum systems, entanglement theory, and more broadly quantum complexity. Despite much progress, a full understanding of monitored many-body dynamics is far from complete, leaving several open questions on the nature of MIPTs, their experimental observability, and the possibilities offered by measurements to enhance control over synthetic quantum matter. These issues persist due to the intrinsic complexity of the problem and the lack of efficient tools to study it, mainly caused by the stochastic character of monitored evolution. This thesis addresses these challenges by expanding the investigation of measurement-induced phenomena in new settings and introducing innovative probes of entanglement and many-body quantum complexity for MIPTs. A core question we investigate is the role of symmetries, non-ergodicity, and especially integrability in measurement-induced criticality, which dramatically affect the non-equilibrium phases. We further explore how these phenomena extend beyond bipartite quantum correlations to multipartite entanglement and quantum non-stabilizerness, highlighting the non-trivial interplay between measurements and complexity notions rooted in quantum information theory. Finally, we focus on the compelling problem of decoherence, modeling how noise spoils entanglement structures. These findings, supported by advanced numerical simulations and theoretical analysis, deepen the current understanding of entanglement, complexity, and integrability in monitored quantum many-body systems, offering new perspectives on their rich behavior. In parallel, we address the experimental problem of dissipation in MIPTs, which is of key relevance for practical implementations. We anticipate the present investigation to foster future research on the nature of monitored dynamical critical phenomena and, more broadly, the applications of measurements in quantum state evolution.
The macroscopic manifestation of quantum coherence in complex many-body systems remains one of the most profound and challenging frontiers in modern physics. While traditional percolation theory successfully describes classical connectivity phase transitions in disordered media, and quantum phase transitions typically focus on zero-temperature Hamiltonian parameter variations, the interplay between network topology and quantum coherence propagation lacks a unifying macroscopic framework. In this paper, we propose the theory of Quantum Coherence Percolation Threshold (QCPT), introducing the concept that quantum coherence can undergo a sudden, non-analytic macroscopic percolation transition across complex networks. We formally define the coherence connection probability, denoted as p_C, and demonstrate that when p_C exceeds a critical threshold p_C*, a global coherent cluster abruptly emerges, characterized by a non-zero macroscopic global coherence measure C_global > 0. By formulating the density matrix evolution, local coherence sharing, and topological constraints over complex graph structures, we establish the analytical foundation for this network-mediated quantum phase transition. This framework bridges quantum information theory, statistical mechanics, and network science, offering a foundational blueprint for understanding macroscopic quantum states in complex environments.
Quantum theory provides an extensive framework for the description of the equilibrium properties of quantum matter. Yet experiments in quantum simulators have now opened up a route towards the generation of quantum states beyond this equilibrium paradigm. While these states promise to show properties not constrained by equilibrium principles, such as the equal a priori probability of the microcanonical ensemble, identifying the general properties of nonequilibrium quantum dynamics remains a major challenge, especially in view of the lack of conventional concepts such as free energies. The theory of dynamical quantum phase transitions attempts to identify such general principles by lifting the concept of phase transitions to coherent quantum real-time evolution. This review provides a pedagogical introduction to this field. Starting from the general setting of nonequilibrium dynamics in closed quantum many-body systems, we give the definition of dynamical quantum phase transitions as phase transitions in time with physical quantities becoming nonanalytic at critical times. We summarize the achieved theoretical advances as well as the first experimental observations, and furthermore provide an outlook to major open questions as well as future directions of research.
This paper establishes the theoretical framework of Many-Body Quantum Frequency Synchronization Criticality (MQFSC), investigating how an ensemble of N interacting quantum systems undergoes a sudden non-equilibrium phase transition from an incoherent state to a frequency-locked collective phase. We introduce the quantum order parameter for frequency synchronization, defined as R_omega = | (1/N) sum_{j=1}^N exp(i omega_j t) |, which shifts from zero to unity when the coupling strength exceeds a sharp critical threshold denoted by K > K_c. Utilizing Lindblad master equations and quantum mean-field approximations, we derive the exact critical coupling condition and characterize the underlying critical phenomena, including quantum fluctuations, critical slowing down, and enhanced multipartite entanglement. These findings bridge non-equilibrium statistical mechanics and quantum information science, opening new avenues for advanced quantum metrology and macroscopic coherence engineering.