24,011 research outputs found
A supersymmetric exotic field theory in (1+1) dimensions. One loop soliton quantum mass corrections
We consider one loop quantum corrections to soliton mass for the
supersymmetric extension of the (1+1)-dimensional scalar field theory with the
potential . First, we compute
the one loop quantum soliton mass correction of the bosonic sector. To do that,
we regularize implicitly such quantity by subtracting and adding its
corresponding tadpole graph contribution, and use the renormalization
prescription that the added term vanishes with the corresponding counterterms.
As a result we get a finite unambiguous formula for the soliton quantum mass
corrections up to one loop order. Afterwards, the computation for the
supersymmetric case is extended straightforwardly and we obtain for the one
loop quantum correction of the SUSY kink mass the expected value previously
derived for the SUSY sine-Gordon and models. However, we also have
found that for a particular value of the parameters, contrary to what was
expected, the introduction of supersymmetry in this model worsens ultraviolet
divergences rather than improving them.Comment: 16 pages, 8 figures; Major modifications included to match version
published in JHE
Kondo Resonance Decoherence by an External Potential
The Kondo problem, for a quantum dot (QD), subjected to an external bias, is
analyzed in the limit of infinite Coulomb repulsion by using a consistent
equations of motion method based on a slave-boson Hamiltonian. Utilizing a
strict perturbative solution in the leads-dot coupling, T, to T^4 and T^6
orders, we calculate the QD spectral density and conductance, as well as the
decoherent rate that drive the systemm from the strong to the weak coupling
regime. Our results indicate thet the weak coupling regime is reached for
voltages larger than a few units of the Kondo temperature.Comment: 5 figure
SL(2,R)-geometric phase space and (2+2)-dimensions
We propose an alternative geometric mathematical structure for arbitrary
phase space. The main guide in our approach is the hidden SL(2,R)-symmetry
which acts on the phase space changing coordinates by momenta and vice versa.
We show that the SL(2,R)-symmetry is implicit in any symplectic structure. We
also prove that in any sensible physical theory based on the SL(2,R)-symmetry
the signature of the flat target "spacetime" must be associated with either
one-time and one-space or at least two-time and two-space coordinates. We
discuss the consequences as well as possible applications of our approach on
different physical scenarios.Comment: 17 pages, no figure
The One Dimensional Damped Forced Harmonic Oscillator Revisited
In this paper we give a general solution to the problem of the damped
harmonic oscillator under the influence of an arbitrary time-dependent external
force. We employ simple methods accessible for beginners and useful for
undergraduate students and professors in an introductory course of mechanics.Comment: 4 Latex page
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