arXiv subjects

Joydip Mitra

Publications and source records attributed to Joydip Mitra.

12 recordsLinked to original sources

arXiv2017

Fermion localization in higher curvature and scalar-tensor theories of gravity

It is well known that in a braneworld model, the localization of fermions on lower dimensional submanifold (say a TeV 3-brane) is governed by the gravity in the bulk which also determines the corresponding phenomenology on the brane. Here we consider a five dimensional warped spacetime where the bulk geometry is governed by higher curvature like F(R) gravity. In such a scenario, we explore the role of higher curvature terms on the localization of bulk fermions which in turn determines the effective radion-fermion coupling on the brane. Our result reveals that for appropriate choices of the higher curvature parameter, the profiles of the massless chiral modes of the fermions may get localized near TeV brane while that for massive Kaluza-Klein (KK) fermions localize towards the Planck brane. We also explore these features in the dual scalar-tensor model by appropriate transformations. The localization property turns out to be identical in both the models. This rules out the possibility of any signature of massive KK fermions in TeV scale collider experiments due to higher curvature gravity effects.

hep-th↗

arXiv2017

Fermion localization in higher curvature spacetime

Fermion localization in a braneworld model in presence of dilaton coupled higher curvature Gauss-Bonnet bulk gravity is discussed. It is shown that the lowest mode of left handed fermions can be naturally localized on the visible brane due to the dilaton coupled higher curvature term without the necessity of any external localizing bulk field.

hep-th↗

arXiv2015

Energy fluctuation and discontinuity of specific heat

Specific heat per particle ($c_v$) of an ideal gas, in many occasions, is interpreted as energy fluctuation per particle ($\triangleε^2$) of the ideal gas through the relation: $\triangleε^2=kT^2c_v$, where $k$ is the Boltzmann constant and $T$ is the temperature. This relationship is true only in the classical limit, and deviates significantly in the quantum degenerate regime. We have analytically explored quantum to classical crossover of this relationship, in particular, for 3-D free Bose and Fermi gases. We also have explored the same for harmonically trapped cases. We have obtained a hump of $\triangleε^2/kT^2c_v^{(\text{cl})}$ around the condensation point for 3-D harmonically trapped Bose gas. We have discussed the possibility of occurring phase transition with discontinuity of heat capacity from existence of such a hump for other Bose and Fermi systems.

cond-mat.stat-mech↗

arXiv2014

Modulus stabilization in higher curvature dilaton gravity

We propose a framework of modulus stabilization in two brane warped geometry scenario in presence of higher curvature gravity and dilaton in bulk space-time. In the prescribed setup we study various features of the stabilized potential for the modulus field, generated by a bulk scalar degrees of freedom with quartic interactions localized on the two 3-branes placed at the orbifold fixed points. We determine the parameter space for the gravidilaton and Gauss-Bonnet required to stabilize the modulus in such higher curvature dilaton gravity setup.

hep-th↗

arXiv2011

Soft supersymmetry breaking with tiny cosmological constant in flux compactified N=1 Supergravity

Using the flux compactification scenario in a generic supergravity model we construct a set of conditions which are necessary to generate de-Sitter or anti de-Sitter vacua for appropriate choices of the parameters in superpotential. It is shown that a mass spectrum consistent with softly broken TeV scale supersymmetry in a minimal supersymmetric standard model at the observable sector can be obtained along with a tiny cosmological constant when the Kahler and superpotential of the hidden sector satisfy a set of general constraints. Constructing a specific model with Kahler and superpotentials which satisfy the above constraints, it is demonstrated that all the hidden sector fields have vacuum expectation values close to Planck scale and the resulting low energy potential does not have any flat direction.

hep-th↗

arXiv2010

Scalar Kaluza-Klein modes in a multiply warped braneworld

The Kaluza-Klein (KK) modes of a massive scalar field on a 3-brane embedded in six dimensional multiply warped spacetime are determined. Due to the presence of warping along both the extra dimensions the KK mass spectrum splits into two closely spaced branches which is a distinct feature of this model compared to the five dimensional Randall-Sundrum model. This new cluster of the KK mode spectrum is expected to have interesting phenomenological implications for the upcoming collider experiments. Such a scenario may also be extended for even larger number of orbifolded extra dimensions.

hep-th↗

arXiv2009

Large dimensional random k circulants

Consider random k-circulants A_{k,n} with n tends to infinity, k=k(n) and whose input sequence \{a_l\}_{l \ge 0} is independent with mean zero and variance one and \sup_n n^{-1}\sum_{l=1}^n \E |a_l|^{2+δ}< \infty for some δ> 0. Under suitable restrictions on the sequence \{k(n)\}_{n \ge 1}, we show that the limiting spectral distribution (LSD) of the empirical distribution of suitably scaled eigenvalues exists and identify the limits. In particular, we prove the following: Suppose g \ge 1 is fixed and p_1 is the smallest prime divisor of g. Suppose P_g=\prod_{j=1}^g E_j where \{E_j\}_{1 \le j \le g} are i.i.d. exponential random variables with mean one. (i) If k^g = -1+ s n where s=1 if g=1 and s = o(n^{p_1 -1}) if g>1, then the empirical spectral distribution of n^{-1/2}A_{k,n} converges weakly in probability to U_1P_g^{1/2g} where U_1 is uniformly distributed over the (2g)th roots of unity, independent of P_g. (ii) If g \ge 2 and k^g = 1+ s n with s = o(n^{p_1-1}) then the empirical spectral distribution of n^{-1/2}A_{k,n} converges weakly in probability to U_2P_g^{1/2g} where U_2 is uniformly distributed over the unit circle in \mathbb R^2, independent of P_g. On the other hand, if k \ge 2, k= n^{o(1)} with \gcd(n,k) = 1, and the input is i.i.d. standard normal variables, then F_{n^{-1/2}A_{k,n}} converges weakly in probability to the uniform distribution over the circle with center at (0,0) and radius r = \exp(\E [ \log \sqrt E_1]). We also show that when n=k^2+1\to \infty, and the input is i.i.d. with finite (2+δ) moment, then the spectral radius, with appropriate scaling and centering, converges to the Gumbel distribution.

math.PR↗

arXiv2009

A critical analysis of thermodynamic properties of braneworld black holes in anti-de Sitter spacetime

Thermodynamic properties of Schwarzschild-Anti de-Sitter (Sch-AdS) and Reissner-Nordström-Anti de-Sitter (RN-AdS) blackholes in 3+1 dimensional spacetime are studied critically with special reference to the warped braneworld black holes with non-vanishing cosmological constant on the brane. Explicit dependence of the thermodynamic variables on the parameters of the braneworld model such as the induced three brane cosmological constant as well as the bulk cosmological constant have been determined. Hawking-Page phase transition has been discussed for both Sch-AdS and RN-AdS black holes. At the phase transition point it is shown that the parameters mass, charge and cosmological constant get correlated by an inequality relation which originates from the background warped geometry model.

hep-th↗

arXiv2009

Kaluza-Klein modes of bulk fields in a generalized Randall-Sundrum scenario

We consider a generalised two brane Randall-Sundrum model with non-zero cosmological constant on the visible TeV brane. Massive Kaluza-Klein modes for various bulk fields namely graviton, gauge field and antisymmetric second rank Kalb-Ramond field in a such generalized Randall-Sundrum scenario are determined. The masses for the Kaluza-Klein excitations of different bulk fields are found to depend on the brane cosmological constant indicating interesting consequences in warped brane particle phenomenology

hep-th↗

arXiv2009

Fermion localization in generalised Randall Sundrum model

A generalized two-brane Randall-Sundrum warped braneworld model admits of solutions of the warp factor for both positive or negative cosmological constant on the visible 3-brane which can resolve the naturalness problem in connection with the fine tuning of Higgs mass in the standard model of elementary particles. To explore the location of the standard model fermions in such a generalized warped model, we, in this work, determine the dependence of the localization profile of a bulk fermion on the brane cosmological constant brane tension and the bulk fermion mass. Our results reveal that for a positive and small value of the induced cosmological constant a bulk fermion is localized close to the brane. On the other hand for a visible brane with negative cosmological constant and positive tension, the fermions are localized inside the bulk leading to phenomenologically interesting possibilities.

hep-th↗

arXiv2009

Modulus stabilization of generalized Randall Sundrum model with bulk scalar field

We study the stabilization of inter-brane spacing modulus of generalized warped brane models with a nonzero brane cosmological constant. Employing Goldberger-Wise stabilization prescription of brane world models with a bulk scalar field, we show that the stabilized value of the modulus generally depends on the value of the brane cosmological constant. Our result further reveals that the stabilized modulus value corresponding to a vanishingly small cosmological constant can only resolve the gauge hierarchy problem simultaneously. This in turn vindicates the original Randall-Sundrum model where the 3-brane cosmological constant was chosen to be zero.

hep-th↗

arXiv2008

Chiral fermions in a spacetime with multiple warping

In a six dimensional brane world model with multiple $S_1/Z_2$ warping, two of the 4-branes at the boundaries have coordinate dependent brane tensions in order to implement the orbifolded boundary conditions consistently. Such brane tension is shown to be equivalent to a scalar field distribution on the brane [1]. We show that in such a scenario a masslesss left chiral fermion on the 4-brane localizes naturally on the standard model 3-brane located at one edge of the compact manifold while the massless right chiral fermion wave function as well as the wave functions for the massive fermion modes peak away from this brane. This offers a mechanism of obtaining massless chiral fermion with only one of its chiral component present in our brane.

hep-th↗