1,474 research outputs found
Dynamical Behavior of the BTZ Black Hole
We study the dynamical behavior of the BTZ (Banados-Teitelboim-Zanelli) black
hole with the low-energy string effective action. The perturbation analysis
around the BTZ black hole reveals a mixing between the dilaton and other
fields. Introducing the new gauge (dilaton gauge), we disentangle this mixing
completely and obtain one decoupled dilaton equation. We obtain the decay rate
of BTZ black hole.Comment: minor typhographical corrections, ReVTeX, 9 pages with no figure
On the stability of black hole event horizons
In this work we study a {\it gedanken} experiment constructed in order to
test the cosmic censorship hypothesis and the second law of black hole
thermo-dynamics. Matter with a negative gravitating energy is imagined added to
a near extremal -charged static black hole in Einstein-Maxwell theory.
The dynamics of a similar process is studied and the thermo-dynamical
properties of the resulting black hole structure is discussed. A new mechanism
which stabilizes black hole event horizons is shown to operate in such
processes.Comment: 16, grammatical errors corrected and two references adde
Causality bounds for neutron-proton scattering
We consider the constraints of causality and unitarity for the low-energy
interactions of protons and neutrons. We derive a general theorem that
non-vanishing partial-wave mixing cannot be reproduced with zero-range
interactions without violating causality or unitarity. We define and calculate
interaction length scales which we call the causal range and the Cauchy-Schwarz
range for all spin channels up to J = 3. For some channels we find that these
length scales are as large as 5 fm. We investigate the origin of these large
lengths and discuss their significance for the choice of momentum cutoff scales
in effective field theory and universality in many-body Fermi systems.Comment: 36 pages, 10 figures, 7 tables, version to appear in Eur. Phys. J.
Multipartite entanglement for entanglement teleportation
The scheme for entanglement teleportation is proposed to incorporate
multipartite entanglement of four qubits as a quantum channel. Based on the
invariance of entanglement teleportation under arbitrary two-qubit unitary
transformation, we derive relations of separabilities for joint measurements at
a sending station and for unitary operations at a receiving station. From the
relations of separabilities it is found that an inseparable quantum channel
always leads to a total teleportation of entanglement with an inseparable joint
measurement and/or a nonlocal unitary operation.Comment: slightly modifie
Bulk and Boundary Dynamics in BTZ Black Holes
Recently, the AdS/CFT conjecture of Maldacena has been investigated in
Lorentzian signature by Balasubramanian et. al. We extend this investigation to
Lorentzian BTZ black hole spacetimes, and study the bulk and boundary behaviour
of massive scalar fields both in the non-extremal and extremal case. Using the
bulk-boundary correspondence, we also evaluate the two-point correlator of
operators coupling to the scalar field at the boundary of the spacetime, and
find that it satisfies thermal periodic boundary conditions relevant to the
Hawking temperature of the BTZ black hole.Comment: 22 pages, LaTeX file. v2: references added. v3: some typo corrections
and minor clarification
Hamiltonian Theory of the Composite Fermion Wigner Crystal
Experimental results indicating the existence of the high magnetic field
Wigner Crystal have been available for a number of years. While variational
wavefunctions have demonstrated the instability of the Laughlin liquid to a
Wigner Crystal at sufficiently small filling, calculations of the excitation
gaps have been hampered by the strong correlations. Recently a new Hamiltonian
formulation of the fractional quantum Hall problem has been developed. In this
work we extend the Hamiltonian approach to include states of nonuniform
density, and use it to compute the excitation gaps of the Wigner Crystal
states. We find that the Wigner Crystal states near are
quantitatively well described as crystals of Composite Fermions with four
vortices attached. Predictions for gaps and the shear modulus of the crystal
are presented, and found to be in reasonable agreement with experiments.Comment: 41 page, 6 figures, 3 table
Hadron Properties with FLIC Fermions
The Fat-Link Irrelevant Clover (FLIC) fermion action provides a new form of
nonperturbative O(a)-improvement in lattice fermion actions offering near
continuum results at finite lattice spacing. It provides computationally
inexpensive access to the light quark mass regime of QCD where chiral
nonanalytic behaviour associated with Goldstone bosons is revealed. The
motivation and formulation of FLIC fermions, its excellent scaling properties
and its low-lying hadron mass phenomenology are presented.Comment: 29 pages, 13 figures, 6 tables. Contribution to lecure notes in 2nd
Cairns Topical Workshop on Lattice Hadron Physics 2003 (LHP 2003), Cairns,
Australia, 22-30 Jul 200
Future cosmological evolution in gravity using two equations of state parameters
We investigate the issues of future oscillations around the phantom divide
for gravity. For this purpose, we introduce two types of energy density
and pressure arisen from the -higher order curvature terms. One has the
conventional energy density and pressure even in the beginning of the Jordan
frame, whose continuity equation provides the native equation of state . On the other hand, the other has the different forms of energy density
and pressure which do not obviously satisfy the continuity equation. This needs
to introduce the effective equation of state to describe the
-fluid, in addition to the native equation of state .
We confirm that future oscillations around the phantom divide occur in
gravities by introducing two types of equations of state. Finally, we point out
that the singularity appears ar because the stability condition of
gravity violates.Comment: 23 pages, 10 figures, correcting typing mistake in titl
Modern topics in theoretical nuclear physics
Over the past five years there have been profound advances in nuclear physics
based on effective field theory and the renormalization group. In this brief,
we summarize these advances and discuss how they impact our understanding of
nuclear systems and experiments that seek to unravel their unknowns. We discuss
future opportunities and focus on modern topics in low-energy nuclear physics,
with special attention to the strong connections to many-body atomic and
condensed matter physics, as well as to astrophysics. This makes it an exciting
era for nuclear physics.Comment: 8 pages, 1 figure, prepared for the Nuclear Physics Town Hall Meeting
at TRIUMF, Sept. 9-10, 2005, comments welcome, references adde
On Thermodynamical Properties of Some Coset CFT Backgrounds
We investigate the thermodynamical features of two Lorentzian signature
backgrounds that arise in string theory as exact CFTs and possess more than two
disconnected asymptotic regions: the 2-d charged black hole and the
Nappi-Witten cosmological model. We find multiple smooth disconnected Euclidean
versions of the charged black hole background. They are characterized by
different temperatures and electro-chemical potentials. We show that there is
no straightforward analog of the Hartle-Hawking state that would express these
thermodynamical features. We also obtain multiple Euclidean versions of the
Nappi-Witten cosmological model and study their singularity structure. It
suggests to associate a non-isotropic temperature with this background.Comment: 1+39 pages, harvmac, 8 eps figure
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