24,747 research outputs found
Fluctuation-dissipation theorem for chiral systems in non-equilibrium steady states
We consider a three-terminal system with a chiral edge channel connecting the
source and drain terminals. Charge can tunnel between the chiral edge and a
third terminal. The third terminal is maintained at a different temperature and
voltage than the source and drain. We prove a general relation for the current
noises detected in the drain and third terminal. It has the same structure as
an equilibrium fluctuation-dissipation relation with the nonlinear response in
place of the linear conductance. The result applies to a general chiral system
and can be useful for detecting "upstream" modes on quantum Hall edges.Comment: detailed proo
Detecting non-Abelian Statistics with Electronic Mach-Zehnder Interferometer
Fractionally charged quasiparticles in the quantum Hall state with filling
factor are expected to obey non-Abelian statistics. We demonstrate
that their statistics can be probed by transport measurements in an electronic
Mach-Zehnder interferometer. The tunneling current through the interferometer
exhibits a characteristic dependence on the magnetic flux and a non-analytic
dependence on the tunneling amplitudes which can be controlled by gate
voltages.Comment: 4 pages, 2 figures; Revtex; a discussion of the asymmetry of the I-V
curve adde
scalar glueball in finite-width Gaussian sum rules
Based on a semiclassical expansion for quantum chromodynamics in the
instanton liquid background, the correlation function of the scalar
glueball current is given, and the properties of the scalar glueball
are studied in the framework of Gaussian sum rules. Besides the pure classical
and quantum contributions, the contributions arising from the interactions
between the classical instanton fields and quantum gluons are come into play.
Instead of the usual zero-width approximation for the resonance, the
Breit-Wigner form for the spectral function of the finite-width resonance is
adopted. The family of the Gaussian sum rules for the scalar glueball in
quantum chromodynamics with and without light quarks is studied. A consistency
between the subtracted and unsubtracted sum rules is very well justified, and
the values of the decay width and the coupling to the corresponding current for
the resonance, in which the scalar glueball fraction is dominant, are
obtained.Comment: 18pages, 9figure
Statistical description of small quantum systems beyond weak-coupling limit
An explicit expression is derived for the statistical description of small
quantum systems, which are relatively-weakly and directly coupled to only small
parts of their environments. The derived expression has a canonical form, but
is given by a renormalized self-Hamiltonian of the studied system, which
appropriately takes into account the influence of the system-environment
interaction. In the case that the system has a narrow spectrum and the
environment is sufficiently large, the modification to the self-Hamiltonian
usually has a mean-field feature, given by an environmental average of the
interaction Hamiltonian. In other cases, the modification may be beyond the
mean-field approximation.Comment: 9 pages, published versio
Chiral restoration at finite temperature with meson loop corrections
We investigate chiral-restoration patterns of QCD for N_{c}=3 and N_{f}=2 at
finite temperature (T) and zero quark-chemical potential beyond the chiral
limit, indicating the explicit chiral-symmetry breaking. To this end, we employ
the instanton-vacuum configuration for the flavor SU(2) sector and the
Harrington-Shepard caloron for modifying relevant instanton parameters as
functions of T. The meson-loop corrections (MLC), which correspond to 1/N_{c}
corrections, are also taken into account to reproduce appropriate m_{q}
dependences of chiral order parameters. We compute chiral condensate as a
function of T and/or m_{q}. From the numerical calculations, we observe that
MLC play an important role to have a correct universality-class behavior of
chiral-restoration patterns in this framework, depending on m_{q}: Second-order
phase transition in the chiral limit, m_{q}=0 and crossover for m_{q}>0.
Without MLC, all the restoration patterns are crossover, due to simple
saddle-point approximations. It turns out that T^{\chi}_{c}=159 MeV in the
chiral limit and T^{\chi}_{c}=(177,186,196) MeV for m_{q}=(5,10,15) MeV, using
the phenomenological choices for the instanton parameters at T=0.Comment: 12 pages, 6 figure
Electronic Mach-Zehnder interferometer as a tool to probe fractional statistics
We study transport through an electronic Mach-Zehnder interferometer recently
devised at the Weizmann Institute. We show that this device can be used to
probe statistics of quasiparticles in the fractional quantum Hall regime. We
calculate the tunneling current through the interferometer as the function of
the Aharonov-Bohm flux, temperature and voltage bias, and demonstrate that its
flux-dependent component is strongly sensitive to the statistics of tunneling
quasiparticles. More specifically, the flux-dependent and flux-independent
contributions to the current are related by a power law, the exponent being a
function of the quasiparticle statistics.Comment: 22 pages; 8 figure
Absorption cross section in warped AdS_3 black hole revisited
We investigate the absorption cross section for minimal-coupled scalars in
the warped AdS_3 black hole. According to our calculation, the cross section
reduces to the horizon area in the low energy limit as usually expected in
contrast to what was previously found. We also calculate the greybody factor
and find that the effective temperatures for the two chiral CFT's are
consistent with that derived from the quasinormal modes. Observing the
conjectured warped AdS/CFT correspondence, we suspect that a specific sector of
the CFT operators with the desired conformal dimension could be responsible for
the peculiar thermal behaviour of the warped AdS_3 black hole.Comment: 16+1 pages, typos corrected, references and footnotes adde
Modified Bennett-Brassard 1984 Quantum Key Distribution With Two-way Classical Communications
The quantum key distribution protocol without public announcement of bases is
equipped with a two-way classical communication symmetric entanglement
purification protocol. This modified key distribution protocol is
unconditionally secure and has a higher tolerable error rate of 20%, which is
higher than previous scheme without public announcement of bases.Comment: 5 pages. To appear in Physical Review
Evidence for the Luttigger liquid density of states in transport across the incompressible stripe at fractional filling factors
We experimentally investigate transport across the incompressible stripe at
the sample edge in the fractional quantum Hall effect regime at bulk filling
factors and . We obtain the dependence of the equilibration
length, that is a phenomenological characteristics of the transport, on the
voltage imbalance and the temperature, at high voltage imbalances. These
dependencies are found to be of the power-law form, which is a strong evidence
for the Luttigger liquid density of states.Comment: 4 pages, to appear in EP
Super-soft symmetry energy encountering non-Newtonian gravity in neutron stars
Considering the non-Newtonian gravity proposed in the grand unification
theories, we show that the stability and observed global properties of neutron
stars can not rule out the super-soft nuclear symmetry energies at
supra-saturation densities. The degree of possible violation of the
Inverse-Square-Law of gravity in neutron stars is estimated using an Equation
of State (EOS) of neutron-rich nuclear matter consistent with the available
terrestrial laboratory data.Comment: Version accepted by Physical Review Letter
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