arXiv subjects

Yoshimasa Hidaka

Publications and source records attributed to Yoshimasa Hidaka.

At least 19 recordsLinked to original sources

arXiv2026

Invariants of Sequential Circuits and Generalized Non-Abelian Statistics

Non-invertible symmetries in quantum many-body systems generally give rise to sequential unitary circuits that move symmetry defects. In this paper, we investigate invariants defined by sequences of such circuits, which move non-invertible defects and generate a Berry phase evaluated on quantum states with defects. We show that this Berry phase generally defines an invariant under local deformations, provided that the sequential circuits preserve the locality of those deformations. This invariant also rules out a short-range-entangled state that preserves the non-invertible symmetry, thereby signaling the 't Hooft anomaly of a non-invertible symmetry purely in terms of unitary operators acting on a state. We then apply this framework to loop excitations in three spatial dimensions and identify a new loop excitation in the (3+1)D $\mathbb{D}_4$ topological order, which we dub a non-Abelian fermionic loop. Using the invariant of sequential circuits, we characterize the statistics of non-Abelian fermionic loops. In addition, we find a new (3+1)D mixed topological order with a single non-Abelian fermionic loop, whose long-range entanglement is protected by an invariant of sequential circuits.

cond-mat.str-el↗

arXiv2026

Dense $\mathrm{QC_2D_2}$ with uniform matrix product states

We study cold dense single-flavor $\mathrm{SU}(2)$ gauge theory in $(1+1)$ dimensions in the thermodynamic limit using a gauge-invariant variational uniform matrix product state ansatz. This formulation provides a sign-problem-free, first-principles approach to dense QCD. We show that, at finite baryon density, the infrared behavior is consistent with a Tomonaga--Luttinger liquid: the central charge is determined to be $c=1$, and the two-point function of the baryon-number density exhibits spatial modulation with the wavenumber predicted by Tomonaga--Luttinger liquid theory. The Luttinger parameter varies smoothly from $K\simeq 1$ in the dilute-baryon regime to $K\simeq 1/2$ at higher densities, suggesting a quarkyonic crossover. Furthermore, the quark distribution reveals the coexistence of a quark Fermi sea with a baryonic infrared description, thereby realizing the quarkyonic picture from first principles.

hep-lat↗

arXiv2026

Onset of thermalization of q-deformed SU(2) Yang-Mills theory on a trapped-ion quantum computer

Nonequilibrium dynamics of quantum many-body systems is one of the main targets of quantum simulations. This focus - together with rapid advances in quantum-computing hardware - has driven increasing applications in high-energy physics, particularly in lattice gauge theories. However, most existing experimental demonstrations remain restricted to (1+1)-dimensional and/or abelian gauge theories, such as the Schwinger model and the toric code. It is essential to develop quantum simulations of nonabelian gauge theories in higher dimensions, addressing realistic problems in high-energy physics. To fill the gap, we demonstrate a quantum simulation of thermalization dynamics in a (2+1)-dimensional $q$-deformed $\mathrm{SU}(2)_3$ Yang-Mills theory using a trapped-ion quantum computer. By restricting the irreducible representations of the gauge fields to the integer-spin sector of $\mathrm{SU}(2)_3$, we obtain a simplified yet nontrivial model described by Fibonacci anyons, which preserves the essential nonabelian fusion structure of the gauge fields. We successfully simulate the real-time dynamics of this model using quantum circuits that explicitly implement $F$-moves. In our demonstrations, the quantum circuits execute up to 47 sequential $F$-moves. We identify idling errors as the dominant error source, which can be effectively mitigated using dynamical decoupling combined with a parallelized implementation of $F$-moves.

hep-lat↗

arXiv2026

Phases of the $q$-deformed $\mathrm{SU}(N)$ Yang-Mills theory at large $N$

We investigate the $(2+1)$-dimensional $q$-deformed $\mathrm{SU}(N)_k$ Yang-Mills theory in the lattice Hamiltonian formalism, which is characterized by three parameters: the number of colors $N$, the coupling constant $g$, and the level $k$. By treating these as tunable parameters, we explore how key properties of the theory, such as confinement and topological order, emerge in different regimes. Employing a variational mean-field analysis that interpolates between the strong- and weak-coupling regimes, we determine the large-$N$ phase structure in terms of the 't Hooft coupling $λ_\mathrm{tH}=g^2N$ and the ratio $k/N$. We find that the topologically ordered phase remains robust at large $N$ under appropriate scalings of these parameters. This result indicates that the continuum limit of large-$N$ gauge theory may be more intricate than naively expected, and motivates studies beyond the mean-field theory, both to achieve a further understanding of confinement in gauge theories and to guide quantum simulations of large-$N$ gauge theories.

hep-lat↗

arXiv2025

Anomaly of conserved and nonconserved axial charges in Hamiltonian lattice gauge theory

We investigate the axial anomaly in Hamiltonian lattice gauge theory. The definition of axial charge operators is ambiguous, especially between conserved and nonconserved axial charges. While these charges appear to differ only by a higher-order term in lattice spacing, they do not coincide in the continuum limit. We demonstrate, through analytical and numerical calculations in 1+1 dimensions, that the conserved axial charge correctly reproduces the axial anomaly relation in continuous spacetime. Our finding would serve as a valuable lesson about doubler artifact in Hamiltonian time evolution of lattice gauge theory.

hep-lat↗

arXiv2025

Shear and bulk viscosity for a pure glue theory using an effective matrix model

At nonzero temperatures, the deconfining phase transition can be analyzed using an effective matrix model to characterize the change in holonomy. The model includes gluons and two-dimensional ghost fields in the adjoint representation, or ``teens''. As ghosts, the teen fields are responsible for the decrease of the pressure as $T \rightarrow T_d$, with $T_d$ the transition temperature for deconfinement. Using the solution of this matrix model for a large number of colors, the parameters of the teen fields are adjusted so that the expectation value of the Polyakov loop is close to the values from the lattice. The shear, $η$, and bulk, $ζ$, viscosities are computed in weak coupling but nonzero holonomy. In the pure glue theory, the value of the Polyakov loop is relatively large in the deconfined phase, $\approx 1/2$ at $T_d$. Consequently, if $s$ is the entropy density, while $η/s$ decreases as $T\rightarrow T_d$, it is still well above the conformal bound. In contrast, $ζ/s$ is largest at $T_d$, comparable to $η/s$, then falls off rapidly with increasing temperature and is negligible by $\sim 2 T_d$.

hep-ph↗

arXiv2025

A New State of Matter between the Hadronic Phase and the Quark-Gluon Plasma?

Lattice-QCD simulations and theoretical arguments hint at the existence of an intermediate phase of strongly interacting matter between a confined hadron gas and a deconfined Quark-Gluon Plasma (QGP). We qualitatively and semi-quantitatively explore and differentiate the phase structures in the temperature window from the QCD pseudo-critical temperature $T_c\simeq 160\;\text{MeV}$ to the pure-gluonic deconfinement temperature $T_d\simeq 285\;\text{MeV}$. We propose a three-regime picture using a hadron resonance gas (HRG) description augmented with the glueball spectrum based on the analysis of a large number, $N_c$, of colors. We estimate the entropy density from our model to confirm that the lattice-QCD data are bracketed with three regimes, i.e., a hadron gas, a QGP, and a new phase for $T_c \lesssim T \lesssim T_d$. In this new phase that we name a Spaghetti of Quarks with Glueballs (SQGB), thermal degrees of freedom of quarks are deconfined, yet gluons remain confined in glueballs. Since the Hagedorn temperature, $T_H\sim 285\;\text{MeV}$, is universal in the meson and the glueball sectors, in the infinite $N_c$ limit, the phase diagram in the plane of the baryon chemical potential and the temperature is reduced to the one with the confined and deconfined phases and Quarkyonic Matter at high density. At large but finite $N_c$, an SQGB window may open between these phases. We point out that the SQGB has interesting similarities with Quarkyonic Matter and that this matter in the large $N_c$ limit is confined as measured by the interaction between heavy quarks, but behaves in other respects like a quasi-free gas of quarks. As a result of the extrapolation to $N_c=3$, we present a revised phase diagram with the SQGB phase bounded by thermal crossovers. Finally, we give a quantitative analysis of chiral symmetry restoration in the SQGB phase.

hep-ph↗

arXiv2025

Photon polarization tensor at finite temperature and density in a magnetic field

We present analytical and numerical calculations for the photon polarization tensor at finite temperature and density in a constant magnetic field. We first discuss the tensor decomposition in the presence of the magnetic field, which breaks rotational symmetry. Then, we analytically perform all the momentum integrations and numerically take the Landau level sum. We confirm that the imaginary part of the photon polarization tensor correctly reproduces the known result from the independent calculation. We utilize the Kramers-Kronig relation to estimate the real part numerically as a function of the momenta, the chemical potential, and the finite temperature. As an application, we consider the real photon limit and estimate the photon decay rate and the Stokes parameter in the hot and dense medium. We specifically quantify the difference between the X-mode and the O-mode with the polarization orthogonal and parallel to the magnetic field. As long as the magnetic field is weak, the decay rate of the X-mode photon is larger than that of the O-mode photon, while the O-mode becomes dominant due to the Landau level suppression of the X-mode at a strong magnetic field. We also find that the eigenmodes of the propagating photon change their polarization state with increasing density.

hep-ph↗

arXiv2025

Phase transition on superfluid vortices in Higgs-Confinement crossover

We propose a novel method to distinguish states of matter by identifying spontaneous symmetry breaking on extended objects, such as vortices, even in the absence of a bulk phase transition. As a specific example, we investigate the phase transition on superfluid vortices in the Higgs-confinement crossover using a $\mathrm{U}(1)_\mathrm{gauge} \times \mathrm{U}(1)_\mathrm{global}$ model. This model exhibits superfluidity of $\mathrm{U}(1)_\mathrm{global}$ symmetry and allows for a crossover between the Higgs and confinement regimes by varying the gauge coupling constant from weak to strong. We demonstrate that, on vortices, spontaneous breaking of the $\mathbb{Z}_2$ flavor symmetry occurs in the weak coupling (Higgs) regime, while it does not in the strong coupling (confinement) regime. We also confirm that those regimes are separated by a second-order phase transition through Monte Carlo simulations, whose universality class corresponds to the two-dimensional Ising model.

hep-th↗

arXiv2025

Dense $\textrm{QCD}_2$ with matrix product states

We study one-flavor $\mathrm{SU}(2)$ and $\mathrm{SU}(3)$ lattice QCD in ($1+1$) dimensions at zero temperature and finite density using matrix product states and the density matrix renormalization group. We compute physical observables such as the equation of state, chiral condensate, and quark distribution function as functions of the baryon number density. As a physical implication, we discuss the inhomogeneous phase at nonzero baryon density, where the chiral condensate is inhomogeneous, and baryons form a crystal. We also discuss how the dynamical degrees of freedom change from hadrons to quarks through the formation of quark Fermi seas.

hep-lat↗

arXiv2025

Quantum circuit for $\mathbb{Z}_3$ lattice gauge theory at nonzero baryon density

$\mathbb{Z}_3$ lattice gauge theory is the simplest discrete gauge theory with three-quark bound states, i.e., baryons. Since it has a finite-dimensional Hilbert space, it can be used for testing quantum simulation of lattice gauge theory at nonzero baryon density. We discuss global and local gauge symmetries and their importance in quantum simulation. We perform quantum emulator calculation and demonstrate how to study the ground state property of baryonic matter.

hep-lat↗

arXiv2025

Geometric conservation in curved spacetime and entropy

We provide an improved definition of new conserved quantities derived from the energy-momentum tensor in curved spacetime by introducing an additional scalar function. We find that the conserved current and the associated conserved charge become geometric under a certain initial condition of the scalar function, and show that such a conserved geometric current generally exists in curved spacetime. Furthermore, we demonstrate that the geometric conserved current agrees with the entropy current in an effective theory of a perfect fluid, thus the conserved charge is the total entropy of the system. While the geometric charge can be regarded as the entropy for a nondissipative fluid, its physical meaning should be investigated for more general cases.

hep-th↗

arXiv2024

Selection rules of topological solitons from non-invertible symmetries in axion electrodynamics

We investigate a relation between non-invertible symmetries and selection rules of topological solitons such as axionic domain walls and magnetic strings in the $(3+1)$-dimensional axion electrodynamics with a massive axion or a massive photon. In the low-energy limit of the phases where either the axion or the photon is massive, we identify non-invertible 0- or 1-form symmetry generators as axionic domain walls or magnetic strings, respectively. By non-invertible transformations on magnetic monopoles or axionic strings, we give constraints on possible configurations of topological solitons in the presence of the monopoles or axionic strings. Our results are consistent with a solution to the axionic domain wall problem by the magnetic monopole. Further, we give a new constraint on a linked configuration of the magnetic and axionic strings.

hep-th↗

arXiv2024

Floquet evolution of the q-deformed \texorpdfstring{SU(3)${}_1$}{SU(3)1} Yang-Mills theory on a two-leg ladder

We simulate Floquet time-evolution of a truncated SU(3) lattice Yang-Mills theory on a two-leg ladder geometry under open boundary conditions using IBM's superconducting 156-qubit device ibm\_fez. To this end, we derive the quantum spin representation of the lattice Yang-Mills theory, and compose a quantum circuit carefully tailored to hard wares, reducing the use of CZ gates. Since it is still challenging to simulate Hamiltonian evolution in present noisy quantum processors, we make the step size in the Suzuki-Trotter decomposition very large, and simulate thermalization dynamics in Floquet circuit composed of the Suzuki-Trotter evolution. We demonstrate that IBM's Heron quantum processor can simulate, by error mitigation, Floqeut thermalization dynamics in a large system consisting of $62$ qubits. Our work would be a benchmark for further quantum simulations of lattice gauge theories using real devices.

hep-lat↗

arXiv2024

$\mathbb{Z}_3$ lattice gauge theory as a toy model for dense QCD

We propose the $(3+1)$-dimensional $\mathbb{Z}_3$ lattice gauge theory coupled with the 2-flavor Wilson-Dirac fermion as a toy model for studying quantum chromodynamics (QCD) at nonzero density. We study its phase diagram in the space of the lattice gauge couplings $g^2$ and the quark chemical potentials $μ$ and discuss the similarity and difference compared with anticipated behaviors of actual QCD. This model also provides a testing ground for various algorithms of the numerical Hamiltonian formalism as its Hilbert space is finite-dimensional in a finite box.

hep-lat↗

arXiv2024

HBT signature for clustered substructures probing primordial inhomogeneity in hot and dense QCD matter

We propose a novel approach to probe primordial inhomogeneity in hot and dense matter which could be realized in non-central heavy-ion collisions. Although the Hanbury Brown and Twiss (HBT) interferometry is commonly used to infer the system size, the cluster size should be detected if substructures emerge in space. We demonstrate that a signal peak in the HBT two-particle correlation stands at the relative momentum corresponding to the spatial scale of pseudo one-dimensional modulation. We assess detectability using the data prepared by an event generator (AMPT model) with clustering implemented in the particle distribution.

hep-ph↗

arXiv2023

Spin relaxation rate for baryons in thermal pion gas

We study the relaxation dynamics of the spin polarization of baryons (nucleon and $Λ$-baryon), in a thermal pion gas as a simple model of the hadronic phase of the QCD plasma produced in relativistic heavy-ion collisions. For this purpose, we formulate the quantum kinetic theory for the spin density matrix of baryons in the leading order of the gradient expansion. Considering the baryon-pion elastic scattering processes as the dominant interaction between baryons and thermal pions, we compute the spin relaxation rate of nucleons and $Λ$-baryons in a pion gas up to temperature 200 MeV. In the case of nucleons, we evaluate the spin relaxation rate in the $s$-channel resonance approximation, based on the known experimental data on $Δ$-resonances. We also estimate the spin relaxation rate for $Λ$-baryons, based on experimental inputs and theoretical models for the low-energy $Λ$$π$ scattering, including the chiral perturbation theory.

hep-ph↗

arXiv2023

Chiral anomaly in a (1+1)-dimensional Floquet system under high-frequency electric fields

We investigate the chiral anomaly in a Floquet system under a time-periodic electric field in (1+1) dimensions. Using the van~Vleck high-frequency expansion, we analytically calculate the chiral current and the pseudo-scalar condensate for massless/massive fermions and how they are balanced with the topological charge. In the high-frequency limit, we find that finite-mass effects are suppressed and the topological charge is dominated by the chirality production. Our calculations show that the information about the chiral anomaly is stored not in the static Floquet Hamiltonian but in the periodic kick operator. The computational steps are useful as the theoretical foundation for higher-dimensional generalization.

hep-ph↗