562 research outputs found
Quantum fidelity for one-dimensional Dirac fermions and two-dimensional Kitaev model in the thermodynamic limit
We study the scaling behavior of the fidelity () in the thermodynamic
limit using the examples of a system of Dirac fermions in one dimension and the
Kitaev model on a honeycomb lattice. We show that the thermodynamic fidelity
inside the gapless as well as gapped phases follow power-law scalings, with the
power given by some of the critical exponents of the system. The generic
scaling forms of for an anisotropic quantum critical point for both
thermodynamic and non-thermodynamic limits have been derived and verified for
the Kitaev model. The interesting scaling behavior of inside the gapless
phase of the Kitaev model is also discussed. Finally, we consider a rotation of
each spin in the Kitaev model around the z axis and calculate through the
overlap between the ground states for angle of rotation and
, respectively. We thereby show that the associated geometric phase
vanishes. We have supplemented our analytical calculations with numerical
simulations wherever necessary.Comment: 10 pages, 8 figure
On the log correction to the black hole area law
Various approaches to black hole entropy yield the area law with logarithmic
corrections, many involving a coefficient 1/2, and some involving 3/2. It is
pointed out here that the standard quantum geometry formalism is not consistent
with 3/2 and favours 1/2.Comment: 4 pages; added new result
Several Trade off Features of Quantum Steering in Distributed Scenario
In the present work, we address the question of how bipartite steering
violation takes place among multi-partite systems (where each sub-system have
Hilbert space dimension restricted to two) based on the maximal violations of
the bipartite steering inequality of the reduced pairwise qubit systems. We
have derived a trade-off relation which is satisfied by those pairwise
bipartite maximal steering violations, which physically can be understood as
providing restrictions on the distribution of steering among subsystems. For a
three-qubit system, it is impossible that all pairs of qubits violate the
steering inequality, and once a pair of qubits violates the steering inequality
maximally, the other two pairs of qubits must both obey the steering
inequality. We also present a complementarity relation between genuine
entanglement present in a tripartite state and maximum bipartite steering
violation by its reduced states.Comment: Close to published versio
The role of potential in the ghost-condensate dark energy model
We consider the ghost-condensate model of dark energy with a generic
potential term. The inclusion of the potential is shown to give greater freedom
in realising the phantom regime. The self-consistency of the analysis is
demonstrated using WMAP7+BAO+Hubble data.Comment: A new sub-section added, 13 pages, 3 figures, LaTex. paper thoroughly
rewritten. arXiv admin note: substantial text overlap with arXiv:1301.4746;
and text overlap with arXiv:1008.2182 by other author
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