arXiv subjects

Yushu Song

Publications and source records attributed to Yushu Song.

8 recordsLinked to original sources

arXiv2017

Entanglement Entropy Evolution under Double-trace Deformation

In this paper, we study the bulk entanglement entropy evolution in conical BTZ black bole background using the heat kernel method. This is motivated by exploring the new examples where quantum corrections of entanglement entropy give the leading contribution. We find that in the large black hole limit the bulk entanglement entropy decreases under the double-trace deformation which is consistent with the holographic $c$ theorem and in the small black hole limit the bulk entanglement entropy increases under the double-trace deformation.

hep-th↗

arXiv2012

Fermi Surface under Magnetism Instability

In this paper, we study the fermionic excitations near the quantum criticality using gauge/gravity duality. This is motivated by exploring the Fermi surface evolution near the quantum criticality. We construct the gravity dual of "paramagnetic-nematic" phase transition in a continuum limit and study the Fermi surface evolution across this quantum phase transition. We find that there exists non-Fermi liquid with the Fermi surface in the "paramagnetic" phase and the Fermi surface disappears in the "nematic" phase.

hep-th↗

arXiv2010

Note on Light-like Tachyon Condensation

In this paper closed string emission and open string pair production from the light-like rolling tachyon solution are calculated in subcritical string theory in the background of a linear dilaton. The rolling light-like tachyon represents the inhomogeneous decay of unstable D-brane. The decay rate is given by the imaginary part of annulus diagram which can be calculated using the boundary state/sigma-model method. It is found that the decay rate is finite in the open string ultraviolet region and depends on tachyon profile in the open string infrared region.

hep-th↗

arXiv2008

Mass Deformation of the Multiple M2 Branes Theory

Based on recent developments, in this letter we study the one parameter deformation of 2+1 dimensional gauge theories with scale invariance and N = 8 supersymmetry, which is expected to be the field theory living on a stack of M2 branes. The deformed gauge theory is defined by a Lagrangian and is based on an infinite set of novel 3-algebras constructed by relaxing the assumption that the invariant metric is positive definite. Under the Higgs mechanism, we can obtain the D-branes world volume theory in the presence of background fluxes.

hep-th↗

arXiv2008

Reheating and Cosmic String Production

We compute the string production rate at the end of inflation, using the string spectrum obtained in \lss in a near-de Sitter space. Our result shows that highly excited strings are hardly produced, thus the simple slow-roll inflation alone does not offer a cosmic string production mechanism.

hep-th↗

arXiv2007

Phase Transition Dynamics and Its Alpha' Corrections

We study the dynamics of the first order phase transition in the holographic hard wall model, namely, Polchinski-Strassler's model and come to the conclusion that the phase transition is incomplete in large N limit with the natural boundary condition. We also consider the string length corrections to both hard wall model and Witten's model, and find that the interesting transition configuration is preserved under the alpha' corrections.

hep-th↗

arXiv2007

A Weak Gravity Conjecture for Scalar Field Theories

We show that the recently proposed weak gravity conjecture\cite{AMNV0601} can be extended to a class of scalar field theories. Taking gravity into account, we find an upper bound on the gravity interaction strength, expressed in terms of scalar coupling parameters. This conjecture is supported by some two-dimensional models and noncommutative field theories.

hep-th↗

arXiv2007

Quantizing Strings in de Sitter Space

We quantize a string in the de Sitter background, and we find that the mass spectrum is modified by a term which is quadratic in oscillating numbers, and also proportional to the square of the Hubble constant.

hep-th↗