arXiv subjects

O. V. Teryaev

Publications and source records attributed to O. V. Teryaev.

At least 19 recordsLinked to original sources

arXiv2026

Entanglement viscosity to entropy density ratio for spin-3/2 theory

It is known that the Minkowski vacuum appears as a thermal medium to an accelerated observer due to the renowned Unruh effect. More recently, it has been shown that at least for lower-spin fields this medium also exhibits a non-zero "entanglement" shear viscosity, which saturates the fundamental Kovtun-Son-Starinets (KSS) bound. We test the universality of this result for higher spins by computing the entanglement viscosity for spin-3/2 fields within the Rarita-Schwinger-Adler (RSA) theory. Strikingly, we obtain a negative viscosity. However, computing the entropy density using the modular Hamiltonian expansion method, we find it is also negative, and the viscosity to entropy ratio saturates the KSS bound. To clarify the origin of the negativity, we use another approach of Zubarev density operator, which gives positive entropy. We also show that RSA theory has many features of a conformal field theory.

hep-th↗

arXiv2026

Causality, the Kovtun-Son-Starinets bound, and a novel sum rule for spectral densities

We directly show that the local ratio of the shear viscosity to the entropy density for Unruh radiation at a finite distance from the horizon is universal and satisfies the relation $ η/s = 1/(4πc_s^2) $, which involves the speed of sound $ c_s $. Since $ c_s^2 \leq 1 $ by causality, this establishes the close connection between the famous Kovtun-Son-Starinets bound and causality. Moreover, we show that the ratio of bulk to shear viscosity saturates another well-known bound for the bulk viscosity, predicted within holographic approach. We also show that the condition of isotropy of thermal radiation in the Rindler space leads to a novel sum rule relating the $ c^{(0)}(μ) $ and $ c^{(2)}(μ) $ spectral densities, and we explicitly demonstrate its validity for conformal field theory and free massive Dirac fields in any number of dimensions. The sum rule provides the validity of Pascal law and bears some similarity with Burkhardt-Cottingham sum rule for spin-dependent parton distributions. Our result suggests a new perspective on dissipative transport phenomena in media undergoing extreme acceleration, such as quark-gluon plasma created in relativistic heavy-ion collisions.

hep-th↗

arXiv2026

Hubble's Law in Heavy Ion Collisions

The evolution of the "microscopic" Hubble parameter related to the expansion of matter born in heavy-ion collisions was obtained for nucleons and pions. The calculations were carried out within the parton-hadron-string dynamics (PHSD) transport model. Au+Au collisions with $\sqrt{s_{NN}} = 7.8$ GeV at $b = 2.5,\ 5.0,\ 7.5$, and $10.0$ fm were considered. A new method for determining the "microscopic" Hubble parameter from simulated data was used. The ballistic motion was obtained for the longitudinal direction after the separation of the nuclei. In earlier times, the evolution of the "microscopic" Hubble parameter in this direction was more complicated. For transverse directions, an exponential low-time asymptotics of the Hubble parameter was observed. The obtained values of the "microscopic" Hubble parameter are about 40 orders of magnitude higher than the cosmological Hubble constant.

nucl-th↗

arXiv2026

Axial Anomaly, entanglement and polarization

The (pion) decays controlled by axial anomaly imply the specific entanglement between photons having also the counterparts for classical electromagnetic waves. This is also a specific case of Eisnstein-Podolsky-Rosen-Bohm-Aharonov effect. The absence of causality and non-locality in (angular) momentum conservation is manifested, being especially clear for the generalization to the case of time rather than space separation corresponds to the polarization of dileptons described by time-like pion transition formfactors which may be studied experimentally. The similar decays in external magnetic field manifest the interplay with vacuum conductivity in external magnetic field and longitudinal polarization of vector mesons observed in heavy-ion collisions.

hep-ph↗

arXiv2025

Gross-Llewellyn Smith sum rule with analytic coupling

We investigate the Gross-Llewellyn Smith sum rule within the framework of analytic QCD. A comparison is performed between experimental data, lattice calculations, and perturbative QCD based on conventional and analytic versions of perturbation theory with different parametrizations for the twist-four contribution. We show that conventional perturbation theory fails to reproduce the data, while the analytic version demonstrates good agreement with experiment and lattice calculations. We also discuss the relation between the Gross-Llewellyn Smith sum rule and the Bjorken sum rule.

hep-ph↗

arXiv2025

Modeling of acceleration in heavy-ion collisions: occurrence of temperature below the Unruh temperature

It has recently been shown that extremely strong electric fields can be created in central collisions of heavy ions, due to which the Schwinger effect can be significant. A direct analogue of the electric field in hydrodynamics is the acceleration of the medium. Using the parton-hadron-string dynamics (PHSD) framework we model the Au-Au collisions at intermediate collision energies $\sqrt{s_{NN}}=4.5-11.5\,$GeV and obtain the spatial distribution of acceleration at different time moments. The present study demonstrates that extremely high acceleration of the order of 1 GeV may be generated in both central and non-central collisions, and that the distribution exhibits a core-corona structure. Consequently, in contrast to the case with an electric field, the Unruh effect is expected to be significant. It is demonstrated that for the confined phase the temperature is less than the Unruh temperature. Conversely, in the deconfined phase, the relationship is inverse. The obtained results thus support the prediction about the existence of states with $T<T_U$ at the early stages of the collision and the associated complementary description of thermalization in terms of the novel phase transition at the Unruh temperature.

nucl-th↗

arXiv2025

QCD with Analytic Coupling: Recent Results

This work provides an overview of recent results obtained in the framework of QCD with analytic coupling. Applications to the polarized Bjorken and Gross-Llewellyn Smith sum rules are considered.

hep-ph↗

arXiv2025

Charge sum rules for quark fragmentation functions

Charge sum rules for quark fragmentation functions are studied. The simultaneous implementation of the conservation of electric and baryon charges, strangeness and isospin symmetry is achieved when the fragmentation to both mesons and baryons is considered. The results are compatible to Gell-Mann--Nishijima formulas and may be the new manifestation of superconformal symmetry between mesons and baryons. The numerical estimates are performed and compared with phenomenological models. The recently suggested violations of sum rules due to Wilson lines contributions are discussed.

hep-ph↗

arXiv2025

Relations of meson and nucleon electromagnetic and gravitational radii with quarks and gluons contributions

The electromagnetic and gravitational form factors of the nucleon determined by quark and gluon contributions are calculated using the momentum transfer dependence of generalized parton distributions with different forms of parton distribution functions obtained by various Collaborations. The power forms of gravitational form factors of quarks and gluons are examined. It is shown that the gluon gravitational radius of the nucleon is comparable to the electromagnetic radius of the proton; however, the quark gravitational radius of the nucleon is less than its electromagnetic radius. It is shown that the gluon gravitational form factor drops faster than the quark gravitational form factor at large transfer momenta and corresponds to the triple form.

hep-ph↗

arXiv2025

Gravitational form factors in the perturbative limit

Generalized distribution amplitudes (GDAs) have attracted significant attention in recent years due to their connection with the energy-momentum tensor (EMT) form factors (FFs). The GDAs can be experimentally accessed through the study of amplitudes in $γ^{\ast} γ\to M_1 M_2$ and $γ^{\ast} \to M_1 M_2 γ$, where $M_1M_2$ is a pseudoscalar meson pair such as $πη$ and $ηη^{\prime}$. In this work, we calculate these amplitudes in the perturbative limit and express the extracted $M_1M_2$ GDAs in terms of meson distribution amplitudes that have been constrained by the previous experiments. Our explicit calculation verifies the existence of a new EMT FF that violates the conservation law of EMT when the hadronic matrix element of the EMT operator is considered separately for each quark flavor. In addition, our result shows that the $M_1M_2$ GDAs are identical in $γ^{\ast} γ\to M_1 M_2$ and $γ^{\ast} \to M_1 M_2 γ$, which confirms the universality of GDAs in the perturbative limit. In the future, the GDAs and the EMT FFs studied in this paper can be probed at Belle II. Our study enhances the accessibility to the $P$-wave GDAs in $γ^{\ast} γ\to M_1 M_2$ and $γ^{\ast} \to M_1 M_2 γ$, and provides a promising approach for searching for exotic hybrid mesons in future experiments.

hep-ph↗

arXiv2024

On Bjorken sum rule: heavy quarks and analytic coupling

We present the results of [1], where good agreement was obtained between calculations within the framework of analytic QCD and experimental data on polarized Bjorken sum rule. The heavy quark contributions are taken into account.

hep-ph↗

arXiv2024

GPDs and gravitational form factors of nucleons (quark and gluon contributions)

Taking into account the recent parameterizations of parton distribution functions (PDFs), % obtained in the recent time, the momentum transfer dependence of generalized parton distributions (GPDs) of nucleons is obtained in the limit $ξ\rightarrow 0$. The gravitational quark and gluon form factors of nucleons are calculated. It is shown that the gluon gravitational radius of the nucleon is comparable to the electromagnetic radius of the proton. The power dependence of form factors is investigated. As a result, it was obtained that the quark gravitational form factor is reproduced by the dipole form, while the form of the gluon gravitation form factor corresponds to the triple form.

hep-ph↗

arXiv2024

Heavy quark contributions in Bjorken sum rule with analytic coupling

We consider heavy quark contributions to the polarized Bjorken sum rule. We found good agreement between the experimental data and the predictions of analytic QCD. To satisfy the limit of photoproduction, we use new representation of the perturbative part of the polarized Bjorken sum rule, proposed recently.

hep-ph↗

arXiv2024

On Bjorken sum rule with analytic coupling

hep-ph↗

arXiv2024

Vector $K^{*}$ mesons in external magnetic field from SU(3) gluodynamics

We explore the ground state energies of the neutral and charged vector $K^{*}$ mesons in the external abelian magnetic field of QCD scale using overlap fermions. We attempt to calculate the magnetic moment and the magnetic dipole polarizability of the $K^{*0}$ and $\bar{K}^{*0}$ mesons and investigate their dependence on the ratio of the strange quark mass to the light quark mass. It is found that the ground state energy and the magnetic dipole polarizability depends on the meson spin projection on the magnetic field axis. This leads to the appearance of dileptonic asymmetry, which can be characterized by the tensor polarizability estimated for the $K^{*0}$ mesons. We obtain that the $g$-factor of the vector $K^{*\pm}$ mesons depends on the $m_s/m_u$ value. Also we do not observe any evidence of the tachyon mode existence for the strange vector mesons.

hep-lat↗

arXiv2024

Bjorken sum rule with analytic coupling

We found good agreement between the experimental data obtained for the polarized Bjorken sum rule and the predictions of analytic QCD, as well as a strong difference between these data and the results obtained in the framework of perturbative QCD. To satisfy the limit of photoproduction and take into account Gerasimov-Drell-Hearn and Burkhardt-Cottingham sum rules, we develope new representation of the perturbative part of the polarized Bjorken sum rule.

hep-ph↗

arXiv2024

Hydrodynamical duals of the gravitational axial anomaly and the cosmological constant

We construct the hydrodynamic expansion for a rotating and accelerated medium in a curved space-time, and establish a duality between the currents related to the cosmological constant and the acceleration. Then we consider the more general case with a non-zero Weyl tensor, and show the relationship between the current in flat space-time and the gravitational axial anomaly. This generalizes the previous derivation to the case with a non-zero Ricci tensor.

hep-th↗

arXiv2023

Unruh effect in curved space-time and hydrodynamics

We consider an accelerated relativistic fluid in four-dimensional (anti-)de Sitter space-time. Analyzing only hydrodynamic equations, we construct the equilibrium stress-energy tensor. We confirm that (A)dS vacuum corresponds to a thermal bath in the accelerated frame with a temperature, depending on the acceleration in a flat higher-dimensional (namely, five-dimensional) space, in which curved space-times are embedded. We develop the duality between hydrodynamics and gravity finding a direct relationship between the transport coefficients in flat and curved space-times.

hep-th↗