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.
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.
120499547
SU(2) Yang-Mills theory in two dimensions
121958150
New states in the lattice Schwinger model
New states are found for the Schwinger model put on a lattice. Their properties are discussed. (AIP)
124943624
Resolution of Inconsistency in the Double-Scaling Limit
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)
119236077
Non-Fermi liquid behavior of the drag and diffusion coefficients in QED plasma
We calculate the drag and diffusion coefficients in low temperature QED plasma and go beyond the leading order approximation. The non-Fermi-liquid behavior of these coefficients are clearly revealed. We observe that the subleading contributions due to the exchange of soft transverse photon in both cases are larger than the leading order terms coming from the longitudinal sector. The results are presented in closed form at zero and low temperature.
121582631
Dark energy, cosmic coincidence and future singularity of the universe
Dark energy model with the equation of state $$p_{DE} =-\rho _{DE} -A\rho _{DE}^\alpha $$, is characterised by four finite life time future singularity of the universe for different values of the parameter $$A$$ and $$\alpha $$ [Nojiri et al. in Phys Rev D 71:063004, 2005]. Since from the matter dominated era to the dark energy dominated era the ratio of the dark energy density to the matter energy density increases as the universe expand for these future singularities, the universe passes through a significant time when the dark energy density and the matter energy density are nearly comparable. Considering $$\frac{1}{r_0 }<r=\frac{\rho _{DE} }{\rho _M }<r_0 $$, where $$r_0$$ is any fixed ratio, we calculate the fraction of total life time of the universe when the universe passes through the coincidental stage for these singularities. It has been found that the fractional time varies as $$\alpha $$ varies within the range for which these finite life time future singularities occur and the fraction is smaller for smaller values of $$r_0 $$. Importance of the fractional time and observational limits onto the values of the parameter $$A$$ and $$\alpha $$ has also been discussed.
15306576
On the UV renormalizability of noncommutative field theories
UV/IR mixing is one of the most important features of noncommutative field theories. As a consequence of this coupling of the UV and IR sectors, the configuration of fields at the zero momentum limit in these theories is a very singular configuration. We show that the renormalization conditions set at a particular momentum configuration with a fixed number of zero momenta, renormalizes the Green's functions for any general momenta only when this configuration has same set of zero momenta. Therefore only when renormalization conditions are set at a point where all the external momenta are nonzero, the quantum theory is renormalizable for all values of nonzero momentum. This arises as a result of different scaling behaviors of Green's functions with respect to the UV cutoff (Λ) for configurations containing different set of zero momenta. We study this in the noncommutative 4 theory and analyse similar results for the Gross-Neveu model at one loop level. We next show this general feature using Wilsonian RG of Polchinski in the globally O(N) symmetric scalar theory and prove the renormalizability of the theory to all orders with an infrared cutoff. In the context of spontaneous symmetry breaking (SSB) in noncommutative scalar theory, it is essential to note the different scaling behaviors of Green's functions with respect to Λ for different set of zero momenta configurations. We show that in the broken phase of the theory the Ward identities are satisfied to all orders only when one keeps an infrared regulator by shifting to a nonconstant vacuum.
119169856
New shell closure for neutron-rich Sn isotopes
The evolution of shell structure away from stability [1]has been a topic of intense theoretical [2, 3] and experi-mental [4–6] studies since last decade. Theoretical stud-ies have identiﬁed diﬀerent reasons for the phenomenonof shell evolution with neutron or proton excess. Amongthe various components of the nucleon - nucleon interac-tion, the spin-orbit, tensor part and three - body eﬀectplay important roles in the shell evolutions [1]. Due totensor interactions, nuclear mean ﬁeld undergoes varia-tions with neutron excess. This leads to monopole mi-gration [2]. It is observed for both proton-rich as well asneutron-rich nuclei. While approaching the neutron dripline, the neutron density becomes very diﬀused [3] whichcan also lead to shell quenching. For exotic light nucleithe well established magic numbers for the stable nu-clei are found to be modiﬁed or new magic numbers haveevolved. At least four doubly magic oxygen isotopes havebeen observed [6–8]. They are
122369912
Interacting holographic dark energy with variable deceleration parameter and accreting black holes in Bianchi type-V universe
In this paper, we have considered the spatially homogeneous and anisotropic Bianchi type-V space time filled with two interacting fluids; dark matter and a hypothetical isotropic fluid as the holographic dark energy components. To obtain an exact solution of the Einstein’s field equations, we used the assumption of time dependent deceleration parameter. We have investigated geometric and kinematic properties of the model. It is observed that the anisotropy parameter of the universe approaches to zero and the universe achieve flatness for large cosmic time. We have shown that this expanding solution is stable against the perturbation with respect to anisotropic spatial directions. We have also studied the evolution of the mass of a black hole embedded in a universe which interacts with a combination of dark matter and dark energy, considering that in the vicinity of the black hole the metric is of Schwarzschild type. We found that the black hole mass increases with the evolution of the universe, and on later epochs the increase in mass stops as dark energy accretion takes over. The results are found to be consistent with recent cosmological observations.