119210365
Floquet Majorana Edge Mode and Non-Abelian Anyons in a Driven Kitaev Model
We theoretically study laser driven nonequilibrium states in the Kitaev honeycomb model with a magnetoelectric cross coupling. We show that a topological spin liquid with a gapless chiral edge mode emerges when we apply an elliptically or circularly polarized laser. This is a strongly correlated quantum spin version of the Floquet topological insulator. In the topological phase, the edge mode is made from Majorana fermions and the bulk has gapped non-Abelian anyon excitations.
54072178
Electric field quench in AdS/CFT
A bstractAn 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 N=2$$ \mathcal{N}=2 $$ 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.
119118548
Turbulent meson condensation in quark deconfinement
Abstract 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.
119301422
Restricted phase-space approximation in real-time stochastic quantization
Abstract We perform and extend real-time numerical simulation of a low-dimensional scalar field theory or a quantum mechanical system using stochastic quantization. After a brief review of the quantization method and the complex Langevin dynamics, we calculate the propagator and make a comparison with analytical results. This is a first step toward general applications, and we focus only on the vacuum properties of the theory; this enables us to handle the boundary condition with the i ϵ prescription in frequency space. While we can control stability of the numerical simulation for any coupling strength, our results turn out to flow into an unphysical fixed-point, which is qualitatively understood from the corresponding Fokker–Planck equation. We propose a simple truncation scheme, “restricted phase-space approximation”, to avoid the unphysical fixed-point. With this method, we obtain stable results at reasonably good accuracy. Finally we give a short discussion on the closed-time path formalism and demonstrate the direct computation of the vacuum expectation value not with the i ϵ prescription but from an explicit construction of the Feynman kernel.
116986876
Strong field physics in condensed matter
There are deep similarities between non-linear QFT studied in high-energy and non-equilibrium physics in condensed matter. Ideas such as the Schwinger mechanism and the Volkov state are deeply related to non-linear transport and photovoltaic Hall effect in condensed matter. Here, we give a review on these relations.
53953635
Rapid Thermalization by Baryon Injection in Gauge/Gravity Duality
Using the AdS/CFT correspondence for strongly coupled gauge theories, we calculate thermalization of mesons caused by a time-dependent change of a baryon number chemical potential. On the gravity side, the thermalization corresponds to a horizon formation on the probe flavor brane in the AdS throat. Since heavy ion collisions are locally approximated by a sudden change of the baryon number chemical potential, we discuss implication of our results to RHIC and LHC experiments, to find a rough estimate of rather rapid thermalization time-scale t_{th} < 1 [fm/c]. We also discuss universality of our analysis against varying gauge theories.
121351952
The infrared spectrum of H-3 + in laboratory and space plasmas
Protonated hydrogen, H 3 + , composed of three protons and two electrons, is the simplest stable polyatomic system. It is the most abundant ionic species in molecular hydrogen plasmas, and it is assumed to play a central role in the chemical evolution of molecular clouds, the birthplace of stars. The existence of this species has been known since its discovery by J.J. Thomson in 1912, but its first spectrum was observed only in 1980. The infrared spectrum has since been extended to higher vibrational and rotational states
53724872
ANOMALOUS DIFFUSE INTERSTELLAR BANDS IN THE SPECTRUM OF HERSCHEL 36. I. OBSERVATIONS OF ROTATIONALLY EXCITED CH AND CH + ABSORPTION AND STRONG, EXTENDED REDWARD WINGS ON SEVERAL DIBs ∗
Anomalously broad diffuse interstellar bands (DIBs) at 5780.5, 5797.1, 6196.0, and 6613.6 A are found in absorption along the line of sight to Herschel 36, the star illuminating the bright Hourglass region of the Hii region Messier 8. Interstellar absorption from excited CH + in the J = 1 level and from excited CH in the J = 3/2 level is also seen. To our knowledge, neither those excited molecular lines nor such strongly extended DIBs have previously been seen in absorption from interstellar gas. These unusual features appear to arise in a small region near Herschel 36 which contains most of the neutral interstellar material in the sight line. The CH + and CH in that region are radiatively excited by strong far-IR radiation from the adjacent infrared source Her 36 SE. Similarly, the broadening of the DIBs toward Herschel 36 may be due to radiative pumping of closely spaced high-J rotational levels of relatively small, polar carrier molecules. If this picture of excited rotational states for the DIB carriers is correct and applicable to most DIBs, the 2.7 K cosmic microwave background may set the minimum widths (about 0.35 A) of known DIBs, with molecular processes and/or local radiation fields producing the larger widths found for the broader DIBs. Despite the intense local UV radiation field within the cluster NGC 6530, no previously undetected DIBs stronger than 10 mA in equivalent width are found in the optical spectrum of Herschel 36, suggesting that neither dissociation nor ionization of the carriers of the known DIBs by this intense field creates new carriers with easily detectable DIB-like features. Possibly related profile anomalies for several other DIBs are noted.
24821293
ANOMALOUS DIFFUSE INTERSTELLAR BANDS IN THE SPECTRUM OF HERSCHEL 36. II. ANALYSIS OF RADIATIVELY EXCITED CH+, CH, AND DIFFUSE INTERSTELLAR BANDS
Absorption spectra toward Herschel 36 (Her 36) for the transitions of CH+ in the J = 1 excited rotational level and for the transitions of CH in the J = 3/2 excited fine structure level have been analyzed. These excited levels are above their ground levels by 40.1?K and ~25.7?K and indicate high radiative temperatures of the environment of 14.6?K and 6.7?K, respectively. The effect of the high radiative temperature is more spectacular in some diffuse interstellar bands (DIBs) observed toward Her 36; remarkable extended tails toward red (ETRs) were observed. We interpret these ETRs as being due to a small decrease of the rotational constants upon excitation of the excited electronic states. Along with radiative pumping of a great many high-J rotational levels, this causes the ETRs. In order to study this effect quantitatively, we have developed a model calculation in which the effects of collisions and radiation are treated simultaneously. The simplest case of linear molecules is considered. It has been found that the ETR is reproduced if the fraction of the variation of the rotational constant, ? ? (B' ? B)/B, is sufficiently high (3%-5%) and the radiative temperature is high (T r > 50?K). Although modeling for general molecules is beyond the scope of this paper, the results indicate that the prototypical DIBs ?5780.5, ?5797.1, and ?6613.6 which show the pronounced ETRs are due to polar molecules that are sensitive to the radiative excitation. The requirement of high ? favors relatively small molecules with three to six heavy atoms. DIBs ?5849.8, ?6196.0, and ?6379.3 that do not show the pronounced ETRs are likely due to non-polar molecules or large polar molecules with small ?.