arXiv subjects

Suvankar Dutta

Publications and source records attributed to Suvankar Dutta.

At least 37 records · Page 2Linked to original sources

arXiv2020

Matrix Model for Riemann Zeta via its Local Factors

We propose the construction of an ensemble of unitary random matrices (UMM) for the Riemann zeta function. Our approach to this problem is `$p$-iecemeal', in the sense that we consider each factor in the Euler product representation of the zeta function to first construct a UMM for each prime $p$. We are able to use its phase space description to write the partition function as the trace of an operator that acts on a subspace of square-integrable functions on the $p$-adic field. This suggests a Berry-Keating type Hamiltonian. We combine the data from all primes to propose a Hamiltonian and a matrix model for the Riemann zeta function.

math-ph↗

arXiv2019

Chern-Simons Theory on Seifert Manifold and Matrix Model

Chern-Simons (CS) theories with rank $N$ and level $k$ on Seifert manifold are discussed. The partition functions of such theories can be written as a function of modular transformation matrices summed over different integrable representations of affine Lie algebra $u(N)_k$ associated with boundary Wess-Zumino-Witten (WZW) model. Using properties of modular transform matrices we express the partition functions of these theories as a unitary matrix model. We show that, the eigenvalues of unitary matrices are discrete and proportional to hook lengths of the corresponding integrable Young diagram. As a result, in the large $N$ limit, the eigenvalue density develops an upper cap. We consider CS theory on $S^2\times S^1$ coupled with fundamental matters and express the partition functions in terms of modular transformation matrices. Solving this model at large $N$ we find the dominant integrable representations and show how large $N$ representations are related to each other by transposition of Young diagrams as a result of level rank duality. Next we consider $U(N)$ CS theory on $S^3$ and observed that in Seifert framing the dominant representation is no longer an integrable representation after a critical value of 't Hooft coupling. We also show that CS on $S^3$ admits multiple (two-gap phase) large $N$ phases with the same free energy.

hep-th↗

arXiv2018

From Phase Space to Integrable Representations and Level-Rank Duality

We explicitly find representations for different large $N$ phases of Chern-Simons matter theory on $S^2\times S^1$. These representations are characterised by Young diagrams. We show that no-gap and lower-gap phase of Chern-Simons-matter theory correspond to integrable representations of $SU(N)_k$ affine Lie algebra, where as upper-cap phase corresponds to integrable representations of $SU(k-N)_k$ affine Lie algebra. We use phase space description of arXiv:0711.0133 to obtain these representations and argue how putting a cap on eigenvalue distribution forces corresponding representations to be integrable. We also prove that the Young diagrams corresponding to lower-gap and upper-cap representations are related to each other by transposition under level-rank duality. Finally we draw phase space droplets for these phases and show how information about eigenvalue and Young diagram descriptions can be captured in topologies of these droplets in a unified way.

hep-th↗

arXiv2018

Light-Cone Reduction vs. TsT transformations : A Fluid Dynamics Perspective

We compute constitutive relations for a charged $(2+1)$ dimensional Schrödinger fluid up to first order in derivative expansion, using holographic techniques. Starting with a locally boosted, asymptotically $AdS$, $4+1$ dimensional charged black brane geometry, we uplift that to ten dimensions and perform $TsT$ transformations to obtain an effective five dimensional local black brane solution with asymptotically Schrödinger isometries. By suitably implementing the holographic techniques, we compute the constitutive relations for the effective fluid living on the boundary of this space-time and extract first order transport coefficients from these relations. Schrödinger fluid can also be obtained by reducing a charged relativistic conformal fluid over light-cone. It turns out that both the approaches result the same system at the end. Fluid obtained by light-cone reduction satisfies a restricted class of thermodynamics. Here, we see that the charged fluid obtained holographically also belongs to the same restricted class.

hep-th↗

arXiv2018

Emergent Phase Space Description of Unitary Matrix Model

We show that large $N$ phases of a $0$ dimensional generic unitary matrix model (UMM) can be described in terms of topologies of two dimensional droplets on a plane spanned by eigenvalue and number of boxes in Young diagram. Information about different phases of UMM is encoded in the geometry of droplets. These droplets are similar to phase space distributions of a unitary matrix quantum mechanics (UMQM) ($(0 + 1)$ dimensional) on constant time slices. We find that for a given UMM, it is possible to construct an effective UMQM such that its phase space distributions match with droplets of UMM on different time slices at large $N$. Therefore, large $N$ phase transitions in UMM can be understood in terms of dynamics of an effective UMQM. From the geometry of droplets it is also possible to construct Young diagrams corresponding to $U(N)$ representations and hence different large $N$ states of the theory in momentum space. We explicitly consider two examples : single plaquette model with $\text{Tr} U^2$ terms and Chern-Simons theory on $S^3$. We describe phases of CS theory in terms of eigenvalue distributions of unitary matrices and find dominant Young distributions for them.

hep-th↗

arXiv2016

First Order Galilean Superfluid Dynamics

We study dynamics of (anomalous) Galilean superfluid up to first order in derivative expansion, both in parity-even and parity-odd sectors. We construct a relativistic system -- null superfluid, which is a null fluid (introduced in [arXiv:1509.04718]) with a spontaneously broken global $U(1)$ symmetry. A null superfluid is in one to one correspondence with Galilean superfluid in one lower dimension, i.e. they have same symmetries, thermodynamics, constitutive relations and are related to each other by a mere choice of basis. The correspondence is based on null reduction, which is known to reduce the Poincaré symmetry of a theory to Galilean symmetry in one lower dimension. To perform this analysis, we use offshell formalism of (super)fluid dynamics, adopting it appropriately to null (super)fluids.

hep-th↗

arXiv2016

Phase Space Distribution of Riemann Zeros

We present the partition function of a most generic $U(N)$ single plaquette model in terms of representations of unitary group. Extremising the partition function in large N limit we obtain a relation between eigenvalues of unitary matrices and number of boxes in the most dominant Young tableaux distribution. Since, eigenvalues of unitary matrices behave like coordinates of free fermions whereas, number of boxes in a row is like conjugate momenta of the same, a relation between them allows us to provide a phase space distribution for different phases of the unitary model under consideration. This proves a universal feature that all the phases of a generic unitary matrix model can be described in terms of topology of free fermi phase space distribution. Finally, using this result and analytic properties of resolvent that satisfy Dyson-Schwinger equation, we present a phase space distribution of unfolded zeros of Riemann zeta function.

hep-th↗

arXiv2016

A Mean-Field Description for AdS Black Hole

In this paper we find an equivalent mean-field description for asymptotically $AdS$ black hole in high temperature limit and in arbitrary dimensions. We obtain a class of mean-field potential for which the description is valid. We explicitly show that there is an one to one correspondence between the thermodynamics of a gas of interacting particles moving under a mean-field potential and an $AdS$ black hole, namely the equation of state, temperature, pressure, entropy and enthalpy of both the systems match. In $3+1$ dimensions, in particular, the mean-field description can be thought of as an ensemble of tiny interacting {\it asymptotically flat} black holes moving in volume $V$ and at temperature $T$. This motivates us to identify these asymptotically flat black holes as microstructure of asymptotically $AdS$ black holes in $3+1$ dimensions.

hep-th↗

arXiv2016

Phase Space Distribution for Two-Gap Solution in Unitary Matrix Model

We analyze the dynamics of weakly coupled finite temperature $U(N)$ gauge theories on $S^3$ by studying a class of effective unitary matrix model. Solving Dyson-Schwinger equation at large $N$, we find that different phases of gauge theories are characterized by gaps in eigenvalue distribution over a unit circle. In particular, we obtain no-gap, one-gap and two-gap solutions at large $N$ for a class of matrix model we are considering. The same effective matrix model can equivalently be written as a sum over representations (or Young diagrams) of unitary group. We show that at large $N$, Young diagrams corresponding to different phases can be classified in terms of discontinuities in number of boxes in two consecutive rows. More precisely, the representation, where there is no discontinuity, corresponds to no-gap and one-gap solution, where as, a diagram with one discontinuity corresponds to two-gap phase, mentioned above. This observation allows us to write a one to one relation between eigenvalue distribution function and Young tableaux distribution function for each saddle point, in particular for two-gap solution. We find that all the saddle points can be described in terms of free fermions with a phase space distribution for no-gap, one-gap and two-gap phases.

hep-th↗

arXiv2015

Equilibrium partition function for nonrelativistic fluids

We construct an equilibrium partition function for a non-relativistic fluid and use it to constrain the dynamics of the system. The construction is based on light cone reduction, which is known to reduce the Poincare symmetry to Galilean in one lower dimension. We modify the constitutive relations of a relativistic fluid, and find that its symmetry broken phase - `null fluid' is equivalent to the non-relativistic fluid. In particular, their symmetries, thermodynamics, constitutive relations, and equilibrium partition function match exactly to all orders in derivative expansion.

hep-th↗

arXiv2015

Null Fluids - A New Viewpoint of Galilean Fluids

This article is a detailed version of our short letter `On equilibrium partition function for non-relativistic fluid' [arXiv:1505.05677] extended to include an anomalous $U(1)$ symmetry. We construct a relativistic system, which we call null fluid and show that it is in one-to-one correspondence with a Galilean fluid living in one lower dimension. The correspondence is based on light cone reduction, which is known to reduce the Poincare symmetry of a theory to Galilean in one lower dimension. We show that the proposed null fluid and the corresponding Galilean fluid have exactly same symmetries, thermodynamics, constitutive relations, and equilibrium partition to all orders in derivative expansion. We also devise a mechanism to introduce $U(1)$ anomaly in even dimensional Galilean theories using light cone reduction, and study its effect on the constitutive relations of a Galilean Fluid.

hep-th↗

arXiv2015

Higher Derivative Corrections to Charged Fluids in 2n Dimensions

We study anomalous charged fluid in $2n$-dimensions ($n\geq 2$) up to sub-leading derivative order. Only the effect of gauge anomaly is important at this order. Using the Euclidean partition function formalism, we find the constraints on different sub-leading order transport coefficients appearing in parity-even and odd sectors of the fluid. We introduce a new mechanism to count different fluid data at arbitrary derivative order. We show that only the knowledge of independent scalar-data is sufficient to find the constraints. In appendix we further extend this analysis to obtain fluid data at sub-sub-leading order (where both gauge and gravitational anomaly contribute) for parity-odd fluid.

hep-th↗

arXiv2014

Entropy current for non-relativistic fluid

We study transport properties of a parity-odd, non-relativistic charged fluid in presence of background electric and magnetic fields. To obtain stress tensor and charged current for the non-relativistic system we start with the most generic relativistic fluid, living in one higher dimension and reduce the constituent equations along the light-cone direction. We also reduce the equation satisfied by the entropy current of the relativistic theory and obtain a consistent entropy current for the non-relativistic system (we call it "canonical form" of the entropy current). Demanding that the non-relativistic fluid satisfies the second law of thermodynamics we impose constraints on various first order transport coefficients. For parity even fluid, this is straight forward; it tells us positive definiteness of different transport coefficients like viscosity, thermal conductivity, electric conductivity etc. However for parity-odd fluid, canonical form of the entropy current fails to confirm the second law of thermodynamics. Therefore, we need to add two parity-odd vectors to the entropy current with arbitrary coefficients. Upon demanding the validity of second law, we see that one can fix these two coefficients exactly.

hep-th↗

arXiv2013

Chern-Simons Superconductor

We study the effect of a bulk Chern-Simons (CS) term on 3+1 dimensional type II superconductor in the context of the AdS/CFT correspondence. We holographically compute the super-current and find that it is non-local in nature. It receives non trivial corrections due to presence of the CS term. Considering a large limit of a parameter "lambda" (we call this limit as long wave length limit), which is effectively the high temperature limit of the theory, we find that this non-local super-current boils down to a local quantity. The leading term (without the CS term) of this current matches with the result of Ginzburg-Landau (GL) theory. We compute the effect of the CS term on GL current and find that the effect is highly suppressed at large temperature (~1/T^4). Finally, free energy of the vortex configuration has been calculated. The free energy also receives non trivial correction at the order of 1/lambda^2 in the long wave length approximation.

hep-th↗

arXiv2013

Dyonic Black Hole and Holography

We study thermodynamic properties of dyonic black hole and its dual field theory. We observe that the phase diagram of a dyonic black hole in constant electric potential and magnetic charge ensemble is similar to that of a Van der Waals fluid with chemical potential. Phase transitions and other critical phenomena have been studied in presence of magnetic charge and chemical potential. We also analyse magnetic properties of dual conformal field theory and observe a ferromagnetic like behavior of boundary theory when the external magnetic field vanishes. Finally, we compute susceptibility of different phases of boundary CFT and find that, depending on the strength of the external magnetic field and temperature, these phases are either paramagnetic or diamagnetic.

hep-th↗

arXiv2013

The fate of flat directions in higher derivative gravity

We discuss the fate of flat directions in higher derivative gravity by studying two explicit examples, namely higher derivative gauged supergravity in five dimensions and higher derivative type IIB string theory in ten dimensions. In the first case, the supersymmetric spinning black hole solution in asymptotically AdS spacetime, found by Gutowski and Reall, is analyzed. In this case we find that the flat direction at the two derivative level is not lifted after addition of higher derivative terms, and as it turns out, this result holds even for non-supersymmetric deformations of the higher derivative action. For the rotating D3-brane solutions in type IIB theory, the dilaton parametrizes a flat direction at leading order, but its fate changes upon including order (α^\prime)^3 supersymmetric higher derivative corrections to the type IIB action, i.e. its leading value gets fixed.

hep-th↗

arXiv2012

Constraints on Anomalous Fluid in Arbitrary Dimensions

Using the techniques developed in arxiv: 1203.3544 we compute the universal part of the equilibrium partition function characteristic of a theory with multiple abelian U(1) anomalies in arbitrary even spacetime dimensions. This contribution is closely linked to the universal anomaly induced transport coefficients in hydrodynamics which have been studied before using entropy techniques. Equilibrium partition function provides an alternate and a microscopically more transparent way to derive the constraints on these transport coefficients. We re-derive this way all the known results on these transport coefficients including their polynomial structure which has recently been conjectured to be linked to the anomaly polynomial of the theory. Further we link the local description of anomaly induced transport in terms of a Gibbs current to the more global description in terms of the partition function .

hep-th↗

arXiv2011

Holographic hydrodynamics: models and methods

We review recent developments in holographic hydrodynamics. We start from very basic discussion on hydrodynamic systems and motivate why string theory is an essential tool to deal with these systems when they are strongly coupled. The main purpose of this review article is to understand different holographic techniques to compute transport coefficients (first order and higher order) and their corrections in presence of higher derivative terms in the bulk Lagrangian. We also mention some open challenges in this subject.

hep-th↗