117489045
Methods and Models for the Study of Decoherence
We shall review methods used in the description of decoherence on particle probes in experiments due to surrounding media. This will include conventional media as well as a model for space-time foam arising from non-critical string theory.
120412772
Renormalization-group approach to the lattice massive Schwinger model
Using Migdal-type recursion relations, the long-distance Coulomb force is found to be screened in the massive Schwinger model on a lattice. (AIP)
123114677
Mixing of operators in Wilson expansions
Abstract The tree-loop theorem of 't Hooft and Veltman is used in Fermi type gauges to show that gauge invariant operators in Wilson expansions mix in general with non-gauge invariant operators. Background field gauges are proposed in which this does not occur. Calculations of anomalous dimensions in these gauges are discussed.
115620347
The Schwinger mechanisms in non-abelian gauge theories
Abstract An alternative to the Higgs-Kibble mechanism for the formulation of spontaneously broken gauge theories has been recently proposed. It is shown how the new procedures can be generalised to the case when non-Abelian gauge groups are present.
8253414
The omega effect for neutral mesons
The possible role of decoherence due to space-time foam is discussed within the context of two models, one based on string/brane theory. and the other based on properties of black hole horizons in general relativity. It is argued that the density matrix satisfies a dissipative master equation, primarily from the study of renormalization group flows in non-critical string theory. This interpretation of the zero mode of the Liouville field as time leads necessarily to the CPT operator being ill defined. One striking consequence is that the quantum mechanical correlations of pair states of neutral mesons produced in meson factories are changed from the usual EPR state. The magnitude of this departure from EPR correlations is characterised by a parameter ω. The predicted value of ω is very small or zero. However it is shown explicitly that the the non-vanishing of ω is only a feature of the model based on string/brane theory.
120565281
Frustration and dynamics
Dynamical models incorporating frustration are discussed in general. In particular, it is shown how self-screening of Yang-Mills fields may lead to models of a generalized Ma-Rudnick genre for the spin-glass.
117065404
Energy Spectrum of Primary Cosmic Rays from Air Shower Observations at Sea Level
122825702
Holographic Dark Energy Model with Quintessence in Bianchi Type-I Space-Time
In this paper, we have studied a homogeneous and anisotropic universe filled with matter and holographic dark energy components. Assuming deceleration parameter to be a constant, an exact solution to Einstein’s field equations in axially symmetric Bianchi type-I line element is obtained. A correspondence between the holographic dark energy models with the quintessence dark energy models is also established. Quintessence potential and the dynamics of the quintessence scalar field are reconstructed, which describe accelerated expansion of the universe.
137947355
Fabrication and Installation of Radio Frequency System for K500 Superconducting Cyclotron at Kolkata
28943117
Physical process first law and increase of horizon entropy for black holes in Einstein-Gauss-Bonnet gravity.
We establish the physical process version of the first law by studying small perturbations of a stationary black hole with a regular bifurcation surface in Einstein-Gauss-Bonnet gravity. Our result shows that when the stationary black hole is perturbed by a matter stress energy tensor and finally settles down to a new stationary state, the Wald entropy increases as long as the matter satisfies the null energy condition.
15196353
UV/IR MIXING IN NONCOMMUTATIVE FIELD THEORIES AND OPEN–CLOSED STRING DUALITY
In this paper we study the phenomenon of UV/IR mixing in noncommutative field theories from the point of view of worldsheet open–closed duality in string theory. New infrared divergences in noncommutative field theories arise as a result of integrating over high momentum modes in the loops. These are believed to come from integrating out additional bulk closed string modes. We analyze this issue in detail for the bosonic theory and further for the supersymmetric theory on the C2/Z2 orbifold. We elucidate on the exact role played by the constant background B-field in this correspondence.