In this study,we investigated worldvolume fermions on the flavor brane in the D0-D4/D8 model,which is holographically equivalent to four-dimensional quantum chromodynamics with instantons or equivalently with a theta ...In this study,we investigated worldvolume fermions on the flavor brane in the D0-D4/D8 model,which is holographically equivalent to four-dimensional quantum chromodynamics with instantons or equivalently with a theta angle.The action involving the worldvolume fermions was obtained by the T-duality rules in string theory,and we accordingly derived their effective five-dimensional and canonical four-dimensional forms by using the systematic dimensional reduction and decomposition of the spinor.Subsequently,we used the AdS/CFT dictionary to evaluate the two-point correlation function as the spectral function for the worldvolume fermions and interpreted the fermions as baryons by analyzing their quantum number with the baryon vertex in holography.In this sense,the interacted action involving the worldvolume fermions and gauge field on the flavor brane was finally derived in holography,which describes the various interactions of mesons and baryons with instantons in the large-N limit.Therefore,this study provides a holographic picture to describe baryons and their interactions based on string theory,particularly in the presence of instantons or a theta angle.展开更多
We study thermoelectric transport under shear strain in two spatial dimensional quantum matter using the holographic duality.General analytic formulae for the DC thermoelectric conductivities subjected to finite shear...We study thermoelectric transport under shear strain in two spatial dimensional quantum matter using the holographic duality.General analytic formulae for the DC thermoelectric conductivities subjected to finite shear strain are obtained in terms of black hole horizon data.Off-diagonal terms in the conductivity matrix also appear at zero magnetic field,resembling an emergent electronic nematicity,which cannot nevertheless be identified with the presence of an anomalous Hall effect.For an explicit model study,we numerically construct a family of strained black holes and obtain the corresponding nonlinear stress-strain curves.We then compute all electric,thermoelectric,and thermal conductivities and discuss the effects of strain.While the shear elastic deformation does not affect the temperature dependence of thermoelectric and thermal conductivities quantitatively,it can strongly change the behavior of the electric conductivity.For both shear hardening and softening cases,we find a clear metal-insulator transition driven by the shear deformation.Moreover,the violation of the previously conjectured thermal conductivity bound is observed for large shear deformation.展开更多
We investigate the physical properties of steady flows in a holographic first-order phase transition model,extending from the thermodynamics at equilibrium to the real-time dynamics far from equilibrium.Through spinod...We investigate the physical properties of steady flows in a holographic first-order phase transition model,extending from the thermodynamics at equilibrium to the real-time dynamics far from equilibrium.Through spinodal decomposition or condensation nuclei,the phase-separated state with non-zero momentum can be achieved.In this scenario,we observe a gap between coexisting phases,arising not only from the variations in energy density,but also from the distinctions in momentum density or longitudinal pressure.These disparities are characterized by flow velocity and latent heat.Furthermore,by introducing an inhomogeneous scalar external source to simulate a fixed obstacle,we reveal the dynamical response of momentum loss in the moving system.Notably,starting from an initial phase-separated state with uniform flow velocity,and subsequently interacting it with an obstacle,we find that the moving high-energy phase exhibits four characteristic dynamical behaviors—rebounding,pinning,passing,and splitting.These behaviors depend on the velocity of the phase and the strength of the obstacle.展开更多
Theta-dependent gauge theories can be studied using holographic duality through string theory in certain spacetimes.By this correspondence we consider a stack of N_0 dynamical DO-branes as D-instantons in the backgrou...Theta-dependent gauge theories can be studied using holographic duality through string theory in certain spacetimes.By this correspondence we consider a stack of N_0 dynamical DO-branes as D-instantons in the background sourced by N_c coincident non-extreme black D4-branes.According to the gauge-gravity duality,this D0-D4 brane system corresponds to Yang-Mills theory with a theta angle at finite temperature.We solve the IIA supergravity action by taking account into a sufficiently small backreaction of the Dinstantons and obtain an analytical solution for our D0-D4-brane configuration.Subsequently,the dual theory in the large N_c limit can be holographically investigated with the gravity solution.In the dual field theory,we find that the coupling constant exhibits asymptotic freedom,as is expected in QCD.The contribution of the theta-dependence to the free energy gets suppressed at high temperatures,which is basically consistent with the calculation using the Yang-Mills instanton.The topological susceptibility in the large N_c limit vanishes,and this behavior remarkably agrees with the implications from the simulation results at finite temperature.Moreover,we finally find a geometrical interpretation of the theta-dependence in this holographic system.展开更多
We study the drag force of a relativistic heavy quark using a holographic QCD model with conformal invariance broken by a background dilaton.The effects of the chemical potential and the confining scale on this quanti...We study the drag force of a relativistic heavy quark using a holographic QCD model with conformal invariance broken by a background dilaton.The effects of the chemical potential and the confining scale on this quantity are analyzed.The drag force in this model is shown to be larger than that of N=4 supersymmetric Yang-Mills(SYM) plasma.In particular,the inclusion of the chemical potential and confining scale both enhance the drag force,in agreement with earlier findings.Moreover,we discuss how the chemical potential and confining scale influence the diffusion coefficient.展开更多
The simplest version of the dynamical holographic QCD model is described by adding the KKSS model action on a dilaton-graviton coupled background,in which the AdS5 metric is deformed by the gluon condensation and furt...The simplest version of the dynamical holographic QCD model is described by adding the KKSS model action on a dilaton-graviton coupled background,in which the AdS5 metric is deformed by the gluon condensation and further deformed by the chiral condensation.In this framework,both the chiral symmetry breaking and linear confinement can be realized.The light-flavor hadron spectra and the pion form factor were investigated,but it was difficult to reconcile the light-flavor hadron spectra and pion form factor.By considering the anomalous 5-dimension mass correction of the scalar field from QCD running coupling,it is found that the light flavor hadron spectra and pion form factor can be described well simultaneously.In particular,the ground state and lower excitation states of the scalar,pseudo scalar,and axial vector meson spectra are improved.However,the vector meson spectra are not sensitive to the anomalous 5-dimension mass correction of the scalar field.展开更多
The Ryu-Takayanagi(RT)formula plays a large role in the current theory of gauge-gravity duality and emergent geometry phenomena.The recent reinterpretation of this formula in terms of a set of"bit threads"is...The Ryu-Takayanagi(RT)formula plays a large role in the current theory of gauge-gravity duality and emergent geometry phenomena.The recent reinterpretation of this formula in terms of a set of"bit threads"is an interesting effort in understanding holography.In this study,we investigate a quantum generalization of the"bit threads"based on a tensor network,with particular focus on the multi-scale entanglement renormalization ansatz(MERA).We demonstrate that,in the large c limit,isometries of the MERA can be regarded as"sources"(or"sinks")of the information flow,which extensively modifies the original picture of bit threads by introducing a new variableρ:density of the isometries.In this modified picture of information flow,the isometries can be viewed as generators of the flow.The strong subadditivity and related properties of the entanglement entropy are also obtained in this new picture.The large c limit implies that classical gravity can emerge from the information flow.展开更多
We perform a potential analysis for the holographic Schwinger effect in a deformed AdS5 model with conformal invariance broken by a background dilaton.We evaluated the static potential by analyzing the classical actio...We perform a potential analysis for the holographic Schwinger effect in a deformed AdS5 model with conformal invariance broken by a background dilaton.We evaluated the static potential by analyzing the classical action of a string attached to a rectangular Wilson loop on a probe D3 brane located at an intermediate position in the bulk AdS space.We observed that the inclusion of the chemical potential tends to enhance the production rate,which is opposite to the effect of the confining scale.In addition,we calculated the critical electric field based on the Dirac-Born-Infeld(DBI)action.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.12005033)the Fundamental Research Funds for the Central Universities(Grant No.3132024192)。
文摘In this study,we investigated worldvolume fermions on the flavor brane in the D0-D4/D8 model,which is holographically equivalent to four-dimensional quantum chromodynamics with instantons or equivalently with a theta angle.The action involving the worldvolume fermions was obtained by the T-duality rules in string theory,and we accordingly derived their effective five-dimensional and canonical four-dimensional forms by using the systematic dimensional reduction and decomposition of the spinor.Subsequently,we used the AdS/CFT dictionary to evaluate the two-point correlation function as the spectral function for the worldvolume fermions and interpreted the fermions as baryons by analyzing their quantum number with the baryon vertex in holography.In this sense,the interacted action involving the worldvolume fermions and gauge field on the flavor brane was finally derived in holography,which describes the various interactions of mesons and baryons with instantons in the large-N limit.Therefore,this study provides a holographic picture to describe baryons and their interactions based on string theory,particularly in the presence of instantons or a theta angle.
基金partially supported by the National Natural Science Foundation of China Grant Nos.12122513,12075298,11991052 and 12047503the Chinese Academy of Sciences Project for Young Scientists in Basic Research YSBR-006.
文摘We study thermoelectric transport under shear strain in two spatial dimensional quantum matter using the holographic duality.General analytic formulae for the DC thermoelectric conductivities subjected to finite shear strain are obtained in terms of black hole horizon data.Off-diagonal terms in the conductivity matrix also appear at zero magnetic field,resembling an emergent electronic nematicity,which cannot nevertheless be identified with the presence of an anomalous Hall effect.For an explicit model study,we numerically construct a family of strained black holes and obtain the corresponding nonlinear stress-strain curves.We then compute all electric,thermoelectric,and thermal conductivities and discuss the effects of strain.While the shear elastic deformation does not affect the temperature dependence of thermoelectric and thermal conductivities quantitatively,it can strongly change the behavior of the electric conductivity.For both shear hardening and softening cases,we find a clear metal-insulator transition driven by the shear deformation.Moreover,the violation of the previously conjectured thermal conductivity bound is observed for large shear deformation.
基金supported by the National Natural Science Foundation of China(Grant Nos.12035016,12075026,12275350,12361141825,12375058,and 12447129)the National Key Research and Development Program of China(Grant No.2021YFC2203001)the China Postdoctoral Science Foundation(Grant No.2024M760691).
文摘We investigate the physical properties of steady flows in a holographic first-order phase transition model,extending from the thermodynamics at equilibrium to the real-time dynamics far from equilibrium.Through spinodal decomposition or condensation nuclei,the phase-separated state with non-zero momentum can be achieved.In this scenario,we observe a gap between coexisting phases,arising not only from the variations in energy density,but also from the distinctions in momentum density or longitudinal pressure.These disparities are characterized by flow velocity and latent heat.Furthermore,by introducing an inhomogeneous scalar external source to simulate a fixed obstacle,we reveal the dynamical response of momentum loss in the moving system.Notably,starting from an initial phase-separated state with uniform flow velocity,and subsequently interacting it with an obstacle,we find that the moving high-energy phase exhibits four characteristic dynamical behaviors—rebounding,pinning,passing,and splitting.These behaviors depend on the velocity of the phase and the strength of the obstacle.
基金Supported by the research startup funds of Dalian Maritime University(02502608)the Fundamental Research Funds for the Central Universities(017192608)
文摘Theta-dependent gauge theories can be studied using holographic duality through string theory in certain spacetimes.By this correspondence we consider a stack of N_0 dynamical DO-branes as D-instantons in the background sourced by N_c coincident non-extreme black D4-branes.According to the gauge-gravity duality,this D0-D4 brane system corresponds to Yang-Mills theory with a theta angle at finite temperature.We solve the IIA supergravity action by taking account into a sufficiently small backreaction of the Dinstantons and obtain an analytical solution for our D0-D4-brane configuration.Subsequently,the dual theory in the large N_c limit can be holographically investigated with the gravity solution.In the dual field theory,we find that the coupling constant exhibits asymptotic freedom,as is expected in QCD.The contribution of the theta-dependence to the free energy gets suppressed at high temperatures,which is basically consistent with the calculation using the Yang-Mills instanton.The topological susceptibility in the large N_c limit vanishes,and this behavior remarkably agrees with the implications from the simulation results at finite temperature.Moreover,we finally find a geometrical interpretation of the theta-dependence in this holographic system.
基金Supported by Guizhou Provincial Key Laboratory Of Computational Nano-Material Science(2018LCNS002)
文摘We study the drag force of a relativistic heavy quark using a holographic QCD model with conformal invariance broken by a background dilaton.The effects of the chemical potential and the confining scale on this quantity are analyzed.The drag force in this model is shown to be larger than that of N=4 supersymmetric Yang-Mills(SYM) plasma.In particular,the inclusion of the chemical potential and confining scale both enhance the drag force,in agreement with earlier findings.Moreover,we discuss how the chemical potential and confining scale influence the diffusion coefficient.
基金Supported in part by the National Natural Science Foundation of China(NSFC)(12235016,12221005,11725523,11735007,12275108)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB34030000,XDPB15)+1 种基金the start-up funding from University of Chinese Academy of Sciences(UCAS)the Fundamental Research Funds for the Central Universities。
文摘The simplest version of the dynamical holographic QCD model is described by adding the KKSS model action on a dilaton-graviton coupled background,in which the AdS5 metric is deformed by the gluon condensation and further deformed by the chiral condensation.In this framework,both the chiral symmetry breaking and linear confinement can be realized.The light-flavor hadron spectra and the pion form factor were investigated,but it was difficult to reconcile the light-flavor hadron spectra and pion form factor.By considering the anomalous 5-dimension mass correction of the scalar field from QCD running coupling,it is found that the light flavor hadron spectra and pion form factor can be described well simultaneously.In particular,the ground state and lower excitation states of the scalar,pseudo scalar,and axial vector meson spectra are improved.However,the vector meson spectra are not sensitive to the anomalous 5-dimension mass correction of the scalar field.
基金Supported in part by the National Natural Science Foundation of China(11975116,11665016,11563006)Jiangxi Science Foundation for Distinguished Young Scientists(20192BCB23007)。
文摘The Ryu-Takayanagi(RT)formula plays a large role in the current theory of gauge-gravity duality and emergent geometry phenomena.The recent reinterpretation of this formula in terms of a set of"bit threads"is an interesting effort in understanding holography.In this study,we investigate a quantum generalization of the"bit threads"based on a tensor network,with particular focus on the multi-scale entanglement renormalization ansatz(MERA).We demonstrate that,in the large c limit,isometries of the MERA can be regarded as"sources"(or"sinks")of the information flow,which extensively modifies the original picture of bit threads by introducing a new variableρ:density of the isometries.In this modified picture of information flow,the isometries can be viewed as generators of the flow.The strong subadditivity and related properties of the entanglement entropy are also obtained in this new picture.The large c limit implies that classical gravity can emerge from the information flow.
基金Supported by the NSFC (11705166)the Fundamental Research Funds for the Central Universities,China University of Geosciences (Wuhan)(CUGL180402)。
文摘We perform a potential analysis for the holographic Schwinger effect in a deformed AdS5 model with conformal invariance broken by a background dilaton.We evaluated the static potential by analyzing the classical action of a string attached to a rectangular Wilson loop on a probe D3 brane located at an intermediate position in the bulk AdS space.We observed that the inclusion of the chemical potential tends to enhance the production rate,which is opposite to the effect of the confining scale.In addition,we calculated the critical electric field based on the Dirac-Born-Infeld(DBI)action.
