Andrei E.Y.,Rutgers University |
Li G.,Rutgers University |
Reports on Progress in Physics | Year: 2012
This review covers recent experimental progress in probing the electronic properties of graphene and how they are influenced by various substrates, by the presence of a magnetic field and by the proximity to a superconductor. The focus is on results obtained using scanning tunneling microscopy, spectroscopy, transport and magnetotransport techniques. © 2012 IOP Publishing Ltd.
Lin S.,Max Planck Institute for Physics |
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2011
In this paper, we derive a critical condition for matter equilibration in heavy ion collisions using a holographic approach. Gravitational shock waves with infinite transverse extension are used to model an infinite nucleus. We construct the trapped surface in the collision of two asymmetric planar shock waves with sources at different depth in the bulk AdS and formulate a critical condition for matter equilibration in the collision of "nuclei" in the dual gauge theory. We find the critical condition is insensitive to the depth of the source closer to the AdS boundary. To understand the origin of the critical condition, we compute the Next-to-Leading Order stress tensor in the boundary field theory due to the interaction of the nuclei and find that the critical condition corresponds to the breaking down of the perturbative expansion. We expect nonperturbative effects are needed to describe black hole formation. © 2011 American Physical Society.
Verbaarschot J.J.M.,SUNY |
Wettig T.,University of Regensburg
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014
We derive exact analytical expressions for the spectral density of the Dirac operator at fixed θ-angle in the microscopic domain of one-flavor QCD. These results are obtained by performing the sum over topological sectors using novel identities involving sums of products of Bessel functions. Because the fermion determinant is not positive definite for negative quark mass, the usual Banks-Casher relation is not valid and has to be replaced by a different mechanism first observed for QCD at nonzero chemical potential. Using the exact results for the spectral density we explain how this mechanism results in a chiral condensate that remains constant when the quark mass changes sign. © 2014 American Physical Society.
Splittorff K.,Copenhagen University |
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012
The microscopic spectral density for lattice QCD with two flavors and maximally twisted mass is computed. The results are given for a fixed index of the Dirac operator and include the leading-order a2 corrections to the chiral Lagrangian due to the discretization errors. The computation is carried out within the framework of Wilson chiral perturbation theory. © 2012 American Physical Society.
Physica A: Statistical Mechanics and its Applications | Year: 2014
We introduce various quantitative and mathematical definitions for price momentum of financial instruments. The price momentum is quantified with velocity and mass concepts originated from the momentum in physics. By using the physical momentum of price as a selection criterion, the weekly contrarian strategies are implemented in South Korea KOSPI 200 and US S&P 500 universes. The alternative strategies constructed by the physical momentum achieve the better expected returns and reward-risk measures than those of the traditional contrarian strategy in weekly scale. The portfolio performance is not understood by the Fama-French three-factor model. © 2014 Elsevier B.V. All rights reserved.