10,782 research outputs found
Thermodynamics of AdS Black Holes in Einstein-Scalar Gravity
We study the thermodynamics of -dimensional static asymptotically AdS
black holes in Einstein gravity coupled to a scalar field with a potential
admitting a stationary point with an AdS vacuum. Such black holes with
non-trivial scalar hair can exist provided that the mass-squared of the scalar
field is negative, and above the Breitenlohner-Freedman bound. We use the Wald
procedure to derive the first law of thermodynamics for these black holes,
showing how the scalar hair (or "charge") contributes non-trivially in the
expression. We show in general that a black hole mass can be deduced by
isolating an integrable contribution to the (non-integrable) variation of the
Hamiltonian arising in the Wald construction, and that this is consistent with
the mass calculated using the renormalised holographic stress tensor and also,
in those cases where it is defined, with the mass calculated using the
conformal method of Ashtekar, Magnon and Das. Similar arguments can also be
given for the smooth solitonic solutions in these theories. Neither the black
hole nor the soliton solutions can be constructed explicitly, and we carry out
a numerical analysis to demonstrate their existence and to provide approximate
checks on some of our thermodynamic results.Comment: 42 pages, 2 figures. Version published in JHEP, plus a "Note Added"
expanding on our definition of "mass" via the first la
Field-only integral equation method for time domain scattering of electromagnetic pulses
The scattering of electromagnetic pulses is described using a non-singular
boundary integral method to solve directly for the field components in the
frequency domain, and Fourier transform is then used to obtain the complete
space-time behavior. This approach is stable for wavelengths both small and
large relative to characteristic length scales. Amplitudes and phases of field
values can be obtained accurately on or near material boundaries. Local field
enhancement effects due to multiple scattering of interest to applications in
microphotonics are demonstrated.Comment: 7 pages, 9 figure
Bound states of the Klein-Gordon equation for vector and scalar general Hulthen-type potentials in D-dimension
We solve the Klein-Gordon equation in any -dimension for the scalar and
vector general Hulth\'{e}n-type potentials with any by using an
approximation scheme for the centrifugal potential. Nikiforov-Uvarov method is
used in the calculations. We obtain the bound state energy eigenvalues and the
corresponding eigenfunctions of spin-zero particles in terms of Jacobi
polynomials. The eigenfunctions are physical and the energy eigenvalues are in
good agreement with those results obtained by other methods for D=1 and 3
dimensions. Our results are valid for value when and for any
value when and D=1 or 3. The % -wave () binding energies for
a particle of rest mass are calculated for the three lower-lying
states using pure vector and pure scalar potentials.Comment: 25 page
- …