372 research outputs found
Meson turbulence at quark deconfinement from AdS/CFT
Based on the QCD string picture at confining phase, we conjecture that the
deconfinement transition always accompanies a condensation of higher meson
resonances with a power-law behavior, "meson turbulence". We employ the AdS/CFT
correspondence to calculate the meson turbulence for
supersymmetric QCD at large and at strong coupling limit, and find that
the energy distribution to each meson level scales as with the
universal scaling . The universality is checked for various ways to
attain the quark deconfinement: a static electric field below/around the
critical value, a time-dependent electric field quench, and a time-dependent
quark mass quench, all result in the turbulent meson condensation with the
universal power around the deconfinement.Comment: 20 pages, 17 figure
Holographic Floquet states: (I) A strongly coupled Weyl semimetal
Floquet states can be realized in quantum systems driven by continuous
time-periodic perturbations. It is known that a state known as the Floquet Weyl
semimetal can be realized when free Dirac fermions are placed in a rotating
electric field. What will happen if strong interaction is introduced to this
system? Will the interaction wash out the characteristic features of Weyl
semimetals such as the Hall response? Is there a steady state and what is its
thermodynamic behavior? We answer these questions using AdS/CFT correspondence
in the supersymmetric massless QCD in a rotating electric field
in the large limit realizing the first example of a "holographic Floquet
state". In this limit, gluons not only mediate interaction, but also act as an
energy reservoir and stabilize the nonequilibrium steady state (NESS). We
obtain the electric current induced by a rotating electric field: In the high
frequency region, the Ohm's law is satisfied, while we recover the DC nonlinear
conductivity at low frequency, which was obtained holographically in a previous
work. The thermodynamic properties of the NESS, e.g., fluctuation-dissipation
relation, is characterized by the effective Hawking temperature that is defined
from the effective horizon giving a holographic meaning to the "periodic
thermodynamic" concept. In addition to the strong (pump) rotating electric
field, we apply an additional weak (probe) electric field in the spirit of the
pump-probe experiments done in condensed matter experiments. Weak DC and AC
probe analysis in the background rotating electric field shows Hall currents as
a linear response, therefore the Hall response of Floquet Weyl semimetals
survives at the strong coupling limit. We also find frequency mixed response
currents, i.e., a heterodyning effect, characteristic to periodically driven
Floquet systems.Comment: 30 pages, 12 figure
Electric Field Quench in AdS/CFT
An electric field quench, a suddenly applied electric field, can induce
nontrivial dynamics in confining systems which may lead to thermalization as
well as a deconfinement transition. In order to analyze this nonequilibrium
transitions,we use the AdS/CFT correspondence for
supersymmetric QCD that has a confining meson sector. We find that the electric
field quench causes the deconfinement transition even when the magnitude of the
applied electric field is smaller than the critical value for the static case
(which is the QCD Schwinger limit for quark-antiquark pair creation). The time
dependence is crucial for this phenomenon, and the gravity dual explains it as
an oscillation of a D-brane in the bulk AdS spacetime. Interestingly, the
deconfinement time takes only discrete values as a function of the magnitude of
the electric field. We advocate that the new deconfinement phenomenon is
analogous to the exciton Mott transition.Comment: 43 pages, 21 figure
Turbulent meson condensation in quark deconfinement
In a QCD-like strongly coupled gauge theory at large N_c, using the AdS/CFT
correspondence, we find that heavy quark deconfinement is accompanied by a
coherent condensation of higher meson resonances. This is revealed in
non-equilibrium deconfinement transitions triggered by static, as well as,
quenched electric fields even below the Schwinger limit. There, we observe a
"turbulent" energy flow to higher meson modes, which finally results in the
quark deconfinement. Our observation is consistent with seeing deconfinement as
a condensation of long QCD strings.Comment: 5 pages, 5 figure
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