Quantum critical point
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Deconfined Quantum Critical Points: Symmetries and Dualities Open
The deconfined quantum critical point (QCP), separating the N\\'eel and\nvalence bond solid phases in a 2D antiferromagnet, was proposed as an example\nof $2+1$D criticality fundamentally different from standard\nLandau-Ginzburg-Wilson-Fis…
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Entanglement Transition in a Monitored Free-Fermion Chain: From Extended Criticality to Area Law Open
We analyze the quantum trajectory dynamics of free fermions subject to continuous monitoring. For weak monitoring, we identify a novel dynamical regime of subextensive entanglement growth, reminiscent of a critical phase with an emergent c…
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Measurement-induced entanglement transitions in the quantum Ising chain: From infinite to zero clicks Open
We investigate measurement-induced phase transitions in the Quantum Ising\nchain coupled to a monitoring environment. We compare two different limits of\nthe measurement problem, the stochastic quantum-state diffusion protocol\ncorrespondi…
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Quantum criticality with two length scales Open
Describing an exotic magnetic transition Phase transitions can be caused by temperature fluctuations or, more exotically, by quantum fluctuations at zero temperature. To describe some of these quantum phase transitions, researchers came up…
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Ferroelectric-Ferroelastic Phase Transition in a Nematic Liquid Crystal Open
Ferroelectric ordering in liquids is a fundamental question of physics. Here, we show that ferroelectric ordering of the molecules causes the formation of recently reported splay nematic liquid-crystalline phase. As shown by dielectric spe…
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Critical Quantum Metrology with a Finite-Component Quantum Phase Transition Open
Physical systems close to a quantum phase transition exhibit a divergent susceptibility, suggesting that an arbitrarily high precision may be achieved by exploiting quantum critical systems as probes to estimate a physical parameter. Howev…
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Ising Superconductivity and Quantum Phase Transition in Macro-Size Monolayer NbSe<sub>2</sub> Open
Two-dimensional (2D) transition metal dichalcogenides (TMDs) have a range of unique physics properties and could be used in the development of electronics, photonics, spintronics, and quantum computing devices. The mechanical exfoliation t…
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Nematic quantum critical point without magnetism in FeSe <sub> 1− <i>x</i> </sub> S <sub> <i>x</i> </sub> superconductors Open
Significance The electronic nematic order that spontaneously breaks rotational symmetry of the system is perhaps one of the most surprising states of matter. A key issue is the relationship between the fluctuations of such nematic order an…
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Superconductivity and non-Fermi liquid behavior near a nematic quantum critical point Open
Significance It has been conjectured that many properties of highly correlated materials, including high-temperature superconductivity, may arise from proximity to a metallic quantum critical point. However, the nature of quantum critical …
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Measurement-induced phase transition: A case study in the nonintegrable model by density-matrix renormalization group calculations Open
We study the effect of local projective measurements on the quantum quench\ndynamics. As a concrete example, a one-dimensional Bose-Hubbard model is\nsimulated by the matrix product state and time-evolving block decimation. We\nmap out a g…
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Non-Hermitian Kondo Effect in Ultracold Alkaline-Earth Atoms Open
We investigate the Kondo effect in an open quantum system, motivated by recent experiments with ultracold alkaline-earth(-like) atoms. Because of inelastic collisions and the associated atom losses, this system is described by a complex-va…
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Entanglement Phase Transition Induced by the Non-Hermitian Skin Effect Open
Recent years have seen remarkable development in open quantum systems effectively described by non-Hermitian Hamiltonians. A unique feature of non-Hermitian topological systems is the skin effect, anomalous localization of an extensive num…
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Quantum correlations and coherence in spin-1 Heisenberg chains Open
We explore quantum and classical correlations along with coherence in the ground states of spin-1 Heisenberg chains, namely the one-dimensional XXZ model and the one-dimensional bilinear biquadratic model, with the techniques of density ma…
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Blue Phosphorene Oxide: Strain-Tunable Quantum Phase Transitions and Novel 2D Emergent Fermions Open
Tunable quantum phase transitions and novel emergent fermions in solid-state materials are fascinating subjects of research. Here, we propose a new stable two-dimensional (2D) material, the blue phosphorene oxide (BPO), which exhibits both…
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Strain-Induced Quantum Phase Transitions in Magic-Angle Graphene Open
We investigate the effect of uniaxial heterostrain on the interacting phase diagram of magic-angle twisted bilayer graphene. Using both self-consistent Hartree-Fock and density-matrix renormalization group calculations, we find that small …
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Slow quenches in a quantum Ising chain: Dynamical phase transitions and topology Open
We study the slow quenching dynamics (characterized by an inverse rate,\n$\\tau^{-1}$) of a one-dimensional transverse Ising chain with nearest neighbor\nferromagentic interactions across the quantum critical point (QCP) and analyze\nthe L…
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Experimental Observation of Equilibrium and Dynamical Quantum Phase Transitions via Out-of-Time-Ordered Correlators Open
The out-of-time-ordered correlators (OTOC), a fundamental concept for quantifying quantum information scrambling, has recently been suggested to be an order parameter to dynamically detect both equilibrium quantum phase transitions (EQPTs)…
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Quantum Critical Regime in a Quadratically Driven Nonlinear Photonic Lattice Open
We study an array of coupled optical cavities in the presence of two-photon driving and dissipation. The system displays a critical behavior similar to that of a quantum Ising model at finite temperature. Using the corner-space renormaliza…
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Duality between the Deconfined Quantum-Critical Point and the Bosonic Topological Transition Open
Recently, significant progress has been made in (2+1)-dimensional conformal field theories without supersymmetry. In particular, it was realized that different Lagrangians may be related by hidden dualities; i.e., seemingly different field…
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Characterizing many-body localization by out-of-time-ordered correlation Open
The out-of-time-ordered (OTO) correlation is a key quantity for quantifying quantum chaoticity and has been recently used in the investigation of quantum holography. Here we use it to study and characterize many-body localization (MBL). We…
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Dynamical signature of fractionalization at a deconfined quantum critical point Open
Deconfined quantum critical points govern continuous quantum phase transitions at which fractionalized (deconfined) degrees of freedom emerge. Here we study dynamical signatures of the fractionalized excitations in a quantum magnet (the ea…
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Evidence for a pressure-induced antiferromagnetic quantum critical point in intermediate-valence UTe <sub>2</sub> Open
Multicomponent superconductivity in intermediate-valence UTe 2 emerges from an antiferromagnetic quantum critical point.
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Observation of Dynamical Quantum Phase Transitions with Correspondence in an Excited State Phase Diagram Open
Dynamical quantum phase transitions are closely related to equilibrium quantum phase transitions for ground states. Here, we report an experimental observation of a dynamical quantum phase transition in a spinor condensate with corresponde…
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Dirty Weyl semimetals: Stability, phase transition, and quantum criticality Open
We study the stability of three-dimensional incompressible Weyl semimetals in\nthe presence of random quenched charge impurities. Combining numerical analysis\nand scaling theory we show that in the presence of sufficiently weak randomness…
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Quantum critical behavior influenced by measurement backaction in ultracold gases Open
Recent realizations of quantum gas microscope offer the possibility of\ncontinuous monitoring of the dynamics of a quantum many-body system at the\nsingle-particle level. By analyzing effective non-Hermitian Hamiltonians of\ninteracting bo…
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Effect of Disorder in a Three-Dimensional Layered Chern Insulator Open
We studied the effects of disorder in a three-dimensional layered Chern insulator, which, in the clean limit, is either a Chern insulator or a Weyl semimetal depending on an interlayer coupling strength. By calculating the localization len…
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Concurrence of dynamical phase transitions at finite temperature in the fully connected transverse-field Ising model Open
We construct the finite-temperature dynamical phase diagram of the fully\nconnected transverse-field Ising model from the vantage point of two disparate\nconcepts of dynamical criticality. An analytical derivation of the classical\ndynamic…
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Numerical Evidence for a Phase Transition in 4D Spin-Foam Quantum Gravity Open
Building on recent advances in defining Wilsonian renormalization group (RG) flows, and the notion of scales in particular, for background-independent theories, we present a first investigation of the renormalization of the 4D spin-foam pa…
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Valence Bond Orders at Charge Neutrality in a Possible Two-Orbital Extended Hubbard Model for Twisted Bilayer Graphene Open
An extended Hubbard model on a honeycomb lattice with two orbitals per site at charge neutrality is investigated with unbiased large-scale quantum Monte Carlo simulations. The Fermi velocity of the Dirac fermions is renormalized as the clu…
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Non-Hermitian Phase Transition from a Polariton Bose-Einstein Condensate to a Photon Laser Open
We propose a novel mechanism for a nonequilibrium phase transition in a\n$U(1)$-broken phase of an electron-hole-photon system, from a Bose-Einstein\ncondensate of polaritons to a photon laser, induced by the non-Hermitian nature\nof the c…