scholarly journals Impurity effect on hysteric magnetoconductance: holographic approach

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Kyung Kiu Kim ◽  
Keun-Young Kim ◽  
Sang-Jin Sin ◽  
Yunseok Seo
Keyword(s):  
Time Reversal ◽  
Spontaneous Magnetization ◽  
Surface States ◽  
Weak Localization ◽  
Impurity Effect ◽  
Dimensional System ◽  
Holographic Approach ◽  
Gauge Gravity ◽  
Similar Phase ◽  
Gravity Duality

Abstract In this paper we study a hysteric phase transition from weak localization phase to hysteric magnetoconductance phase using gauge/gravity duality. This hysteric phase is triggered by a spontaneous magnetization related to ℤ2 symmetry and time reversal symmetry in a 2+1 dimensional system with momentum relaxation. We derive thermoelectric conductivity formulas describing non-hysteric and hysteric phases. At low temperatures, this magnetoconductance shows similar phase transitions of topological insulator surface states. We also obtain hysteresis curves of Seebeck coefficient and Nernst signal. It turns out that our impurity parameter changes magnetic properties of the dual system. This is justified by showing increasing susceptibility and the spontaneous magnetization with increasing impurity parameter.

scholarly journals Holographic approach of the spinodal instability to criticality

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Maximilian Attems
Keyword(s):  
Surface Tension ◽  
Critical Point ◽  
Single Phase ◽  
Transverse Pressure ◽  
First Order Phase Transition ◽  
Holographic Approach ◽  
Spinodal Instability ◽  
First Order Phase ◽  
Gauge Gravity ◽  
Gravity Duality

Abstract A smoking gun signature for a first-order phase transition with negative speed of sound squared $$ {c}_s^2 $$ c s 2 is the occurrence of a spinodal instability. In the gauge/gravity duality it corresponds to a Gregory-Laflamme type instability, which can be numerically simulated as the evolution of unstable planar black branes. Making use of holography its dynamics is studied far from and near a critical point with the following results. Near a critical point the interface between cold and hot stable phases, given by its width and surface tension, is found to feature a wider phase separation and a smaller surface tension. Far away from a critical point the formation time of the spinodal instability is reduced. Across softer and harder phase transitions, it is demonstrated that mergers of equilibrated peaks and unstable plateaux lead to the preferred final single phase separated solution. Finally, a new atypical setup with dissipation of a peak into a plateau is discovered. In order to distinguish the inhomogeneous states I propose a new criterium based on the maximum of the transverse pressure at the interface which encodes phase-mixed peaks versus fully phase separated plateaux.

scholarly journals Discovery of a weak topological insulating state and van Hove singularity in triclinic RhBi2

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kyungchan Lee ◽  
Gunnar F. Lange ◽  
Lin-Lin Wang ◽  
Brinda Kuthanazhi ◽  
Thaís V. Trevisan ◽  
...  
Keyword(s):  
Time Reversal ◽  
Topological Insulators ◽  
Dirac Point ◽  
Saddle Points ◽  
Surface States ◽  
Van Hove Singularity ◽  
Space Group ◽  
Topological Materials ◽  
Topological Surface ◽  
Optimal Space

AbstractTime reversal symmetric (TRS) invariant topological insulators (TIs) fullfil a paradigmatic role in the field of topological materials, standing at the origin of its development. Apart from TRS protected strong TIs, it was realized early on that more confounding weak topological insulators (WTI) exist. WTIs depend on translational symmetry and exhibit topological surface states only in certain directions making it significantly more difficult to match the experimental success of strong TIs. We here report on the discovery of a WTI state in RhBi2 that belongs to the optimal space group P$$\bar{1}$$ 1 ¯ , which is the only space group where symmetry indicated eigenvalues enumerate all possible invariants due to absence of additional constraining crystalline symmetries. Our ARPES, DFT calculations, and effective model reveal topological surface states with saddle points that are located in the vicinity of a Dirac point resulting in a van Hove singularity (VHS) along the (100) direction close to the Fermi energy (EF). Due to the combination of exotic features, this material offers great potential as a material platform for novel quantum effects.

scholarly journals Gauge/gravity duality and meta-stable dynamical supersymmetry breaking

2007 ◽  
Vol 2007 (01) ◽  
pp. 083-083 ◽  
Author(s):  
Riccardo Argurio ◽  
Matteo Bertolini ◽  
Sebastián Franco ◽  
Shamit Kachru
Keyword(s):  
Supersymmetry Breaking ◽  
Gauge Gravity ◽  
Gravity Duality

A DIRECT TEST OF THE GAUGE/GRAVITY DUALITY AND THE STRING THEORETICAL DESCRIPTION OF A BLACK HOLE

2008 ◽  
Vol 23 (14n15) ◽  
pp. 2161-2164 ◽  
Author(s):  
JUN NISHIMURA
Keyword(s):  
Black Hole ◽  
Theoretical Description ◽  
Direct Test ◽  
Strongly Coupled ◽  
Open Strings ◽  
Large N ◽  
Brane Solution ◽  
Gauge Gravity ◽  
Gravity Duality ◽  
Microscopic Origin

We perform a direct test of the gauge/gravity duality by studying one-dimensional U (N) gauge theory with 16 supercharges at finite temperature using Monte Carlo simulation. In the 't Hooft large-N limit and in the strong coupling limit, the model is expected to have a dual gravity description in terms of the near-extremal black 0-brane solution in ten-dimensional type IIA supergravity. Our results provide the first example, in which the microscopic origin of the black hole thermodynamics is accounted for by solving explicitly the strongly coupled dynamics of the open strings attached to the D-branes.

scholarly journals Thermodynamics of quasiconformal theories from gauge/gravity duality

2010 ◽  
Vol 82 (5) ◽  
Author(s):  
Janne Alanen ◽  
Keijo Kajantie ◽  
Kimmo Tuominen
Keyword(s):  
Gauge Gravity ◽  
Gravity Duality

Generalized information and entanglement entropy, gravitation and holography

2015 ◽  
Vol 30 (16) ◽  
pp. 1530039 ◽  
Author(s):  
O. Obregón
Keyword(s):  
Entanglement Entropy ◽  
Ideal Gas ◽  
Einstein Equations ◽  
Von Neumann Entropy ◽  
Nonextensive Statistical Mechanics ◽  
Von Neumann ◽  
H Theorem ◽  
Gauge Gravity ◽  
Gravity Duality ◽  
Correction Terms

A nonextensive statistical mechanics entropy that depends only on the probability distribution is proposed in the framework of superstatistics. It is based on a Γ(χ2) distribution that depends on β and also on pl. The corresponding modified von Neumann entropy is constructed; it is shown that it can also be obtained from a generalized Replica trick. We further demonstrate a generalized H-theorem. Considering the entropy as a function of the temperature and volume, it is possible to generalize the equation of state of an ideal gas. Moreover, following the entropic force formulation a generalized Newton's law is obtained, and following the proposal that the Einstein equations can be deduced from the Clausius law, we discuss on the structure that a generalized Einstein's theory would have. Lastly, we address the question whether the generalized entanglement entropy can play a role in the gauge/gravity duality. We pay attention to 2d CFT and their gravity duals. The correction terms to the von Neumann entropy result more relevant than the usual UV ones and also than those due to the area dependent AdS3 entropy which result comparable to the UV ones. Then the correction terms due to the new entropy would modify the Ryu–Takayanagi identification between the CFT entanglement entropy and the AdS entropy in a different manner than the UV ones or than the corrections to the AdS3 area dependent entropy.

scholarly journals Numerical tests of the gauge/gravity duality conjecture for D0-branes at finite temperature and finite N

2016 ◽  
Vol 94 (8) ◽  
Author(s):  
Masanori Hanada ◽  
Yoshifumi Hyakutake ◽  
Goro Ishiki ◽  
Jun Nishimura
Keyword(s):  
Finite Temperature ◽  
Numerical Tests ◽  
Gauge Gravity ◽  
Gravity Duality
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