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In this work, we have studied various mixed state information theoretic quantities for an excited state of Lifshitz spacetime in $3+1$-dimensions. This geometry is the gravity dual to a class of $2+1$-dimensional quantum field theories having Lifshitz symmetry. We have holographically calculated mutual information, entanglement wedge cross section, entanglement negativity and mutual complexity for strip like subsystems at the boundary. For this we have used the results of holographic entanglement entropy and complexity present in the literature. We first calculate all of these mentioned quantities for the pure state of Lifshitz spacetime. Then we have moved on to calculate all these quantities for excited state of the Lifshitz spacetime. The gravity dual of excited state of Lifshitz systems in field theory can be obtained by applying constant perturbations along the boundary direction. Further, we would like to mention that for the simplicity of calculation we are only considering results up to the first order in perturbation. The change in the obtained holographic information theoretic quantities are then related to entanglement entropy, entanglement pressure, entanglement chemical potential and charge using the stress tensor complex. These relations are analogous to the first law of entanglement thermodynamics given earlier in the literature. All the calculations are carried out for both values of dynamical scaling exponent ($z$) present in the Lifshitz field theory., Comment: v1: 51 pages LaTex, multiple figures, v2: matches with the published version

In this work, we extend the study in \href{https://link.springer.com/article/10.1007/JHEP11(2022)013}{JHEP11(2022)013} incorporating the AdS/CFT duality to establish a relationship between the local temperatures (Tolman temperatures) of a large (AdS) spherical and a (AdS) planar Schwarzschild black hole near the AdS boundary considering Gauss-Bonnet curvature correction in the gravitational action. We have shown that the higher curvature corrections appear in the local temperature relationship due to the inclusion of Gauss-Bonnet term in the bulk. By transforming the metric into Fefferman-Graham form, we have calculated the energy density of the conformal fluid at the boundary. The obtained result contains finite coupling corrections which are holographically induced by the Gauss-Bonnet curvature correction in the bulk theory. Following the well known approach of fluid/gravity duality, the energy density of the conformal fluid at the boundary is then compared with the black body radiation energy density. This comparison shows that the energy density is proportional to the temperature of the conformal fluid. The temperature of the conformal fluid is then shown to be related to the Tolman temperature of the black hole which then eventually helps us to establish both the Hawking temperature and Tolman temperature relationship between large spherically symmetric and planar Schwarzschild black holes in Gauss-Bonnet gravity near the AdS boundary., Comment: v1: 17 pages LaTex, v2: 23 pages & multiple new figures, to appear in Classical and Quantum Gravity

Employing $\textit{ab-initio}$ density functional theory (DFT), we performed a systematic investigation of the electronic structures and the magnetic properties of atomic bilayers composed of a 4$d$ transition-metal layer (Rh, Pd and Ru) and a Co layer on the Re(0001) surface. Our DFT calculations reveal the influence of the bilayer composition and their stacking sequence on the magnetic ground state and magnetic interactions. We obtain the magnetic interactions by mapping the total energies onto an effective spin Hamiltonian which contains the exchange interaction and the Dzyaloshinskii-Moriya interaction (DMI) as well as the magnetocrystalline anisotropy energy (MAE). We observe noticeable changes in bilayer hybridization due to variation in bilayer composition and overlayer symmetry, leading to significant variation in magnetic interactions. In all considered systems, the nearest-neighbor exchange interaction is ferromagnetic, however, the value varies by up to a factor of 5. The effective, nearest-neighbor DMI constant exhibits variation in sign over the films considered, favoring either right- (clockwise) or left-handed (anticlockwise) cycloidal spin spirals. The value of the DMI changes by up to a factor of 27 among the films. For most of the systems, the MAE favors an out-of-plane easy magnetization axis, however, for hcp-Co/Rh and hcp-Co/Ru bilayers on Re(0001), it prefers an in-plane magnetization axis. The magnitude of the MAE varies from a small value of about 0.1 meV/Co atom up to about 2 meV/Co atom for Co/Pd bilayers. The spin spiral energy dispersion curve rises quite quickly close to the ferromagnetic state for films in which the Co layer is adjacent to the vacuum indicating a large effective exchange constant which stabilizes a ferromagnetic ground state in Co/$4d$ bilayers on Re(0001).

Machine Learning (ML)-powered apps are used in pervasive devices such as phones, tablets, smartwatches and IoT devices. Recent advances in collaborative, distributed ML such as Federated Learning (FL) attempt to solve privacy concerns of users and data owners, and thus used by tech industry leaders such as Google, Facebook and Apple. However, FL systems and models are still vulnerable to adversarial membership and attribute inferences and model poisoning attacks, especially in FL-as-a-Service ecosystems recently proposed, which can enable attackers to access multiple ML-powered apps. In this work, we focus on the recently proposed Sponge attack: It is designed to soak up energy consumed while executing inference (not training) of ML model, without hampering the classifier's performance. Recent work has shown sponge attacks on ASCI-enabled GPUs can potentially escalate the power consumption and inference time. For the first time, in this work, we investigate this attack in the mobile setting and measure the effect it can have on ML models running inside apps on mobile devices., Comment: 2 pages, 6 figures. Proceedings of the 24th International Workshop on Mobile Computing Systems and Applications (HotMobile). Feb. 2023

Simulation of turbulent flows, especially at the edges of clouds in the atmosphere, is an inherently challenging task. Hitherto, the best possible computational method to perform such experiments is the Direct Numerical Simulation (DNS). DNS involves solving non-linear partial differential equations for fluid flows, also known as Navier-Stokes equations, on discretized grid boxes in a three-dimensional space. It is a valuable paradigm that has guided the numerical weather prediction models to compute rainfall formation. However, DNS cannot be performed for large domains of practical utility to the weather forecast community. Here, we introduce DeepClouds.ai, a 3D-UNET that simulates the outputs of a rising cloud DNS experiment. The problem of increasing the domain size in DNS is addressed by mapping an inner 3D cube to the complete 3D cube from the output of the DNS discretized grid simulation. Our approach effectively captures turbulent flow dynamics without having to solve the complex dynamical core. The baseline shows that the deep learning-based simulation is comparable to the partial-differential equation-based model as measured by various score metrics. This framework can be used to further the science of turbulence and cloud flows by enabling simulations over large physical domains in the atmosphere. It would lead to cascading societal benefits by improved weather predictions via advanced parameterization schemes.

To realize future spintronic applications with magnetic skyrmions -- topologically nontrivial swirling spin structures -- it is essential to achieve efficient writing and deleting capabilities of these quasi-particles. Electric-field assisted nucleation and annihilation is a promising route, however, the understanding of the underlying microscopic mechanisms is still limited. Here, we show how the stability of individual magnetic skyrmions in an ultrathin transition-metal film can be controlled via external electric fields. We demonstrate based on density functional theory that it is important to consider the changes of all interactions with electric field, i.e., the pair-wise exchange, the Dzyaloshinskii-Moriya interaction, the magnetocrystalline anisotropy energy, and the higher-order exchange interactions. The energy barriers for electric-field assisted skyrmion writing and deleting obtained via atomistic spin simulations vary by up to a factor of three more than the variations of the interactions calculated from first-principles. This surprising effect originates from the electric-field dependent size of metastable skyrmions at a fixed magnetic field. The large changes of lifetimes allow the possibility of electric-field assisted thermally activated writing and deleting of skyrmions.

We report the estimation of jet transport coefficient, $\hat{q}$ for quark- and gluon-initiated jets using a simple quasi-particle model in absence and presence of magnetic field. This model introduces a temperature and magnetic field-dependent degeneracy factor of partons, which is tuned by fitting the entropy density of lattice quantum chromodynamics data. At a finite magnetic field, $\hat{q}$ for quark jets splits into parallel and perpendicular components whose magnetic field dependence comes from two sources: the field-dependent degeneracy factor and the phase space part guided from the shear viscosity to entropy density ratio. Due to the electrically neutral nature of gluons, the estimation of $\hat{q}$ for gluon jets is affected only by the field-dependent degeneracy factor. In presence of a finite magnetic field, we find a significant enhancement in $\hat{q}$ for both quark- and gluon-initiated jets at low temperature, which gradually decreases towards high temperature. We compare the obtained results with the earlier calculations based on the anti-de Sitter/conformal field theory correspondence, and a qualitatively similar trend is observed. The change in $\hat{q}$ in presence of magnetic field is, however, quantitatively different for quark- and gluon-initiated jets. This is an interesting observation which can be explored experimentally to verify the effect of magnetic field on $\hat{q}$., Comment: typos corrected, references added, results updated

We have studied the collisional time and relaxation time of a QGP(Quark-Gluon Plasma) by parameterizing them by temperature. From this parameterization we have obtained the decay rate parameterized by temperature which further helps us to calculate and compare the shear viscosity to entropy density ratio of a QGP with the KSS(Kovtun-Son-Starinets) result., Comment: http://sympnp.org/snp2019/

We have parameterized the degeneracy factor in terms of temperature and using this we have tried to compare and study the LQCD(Lattice Quantum Chromodynamics) data with our data., Comment: http://sympnp.org/snp2019/. arXiv admin note: text overlap with arXiv:1908.04330

Effect of quantum chromodynamics (QCD) interaction in quark-gluon plasma on electrical conductivity is studied, where lattice quantum chromodynamics (LQCD) results are mapped through quark and gluon degeneracy., Comment: Conference proceeding in 64th DAE-BRNS Symposium on Nuclear Physics, Link- http://sympnp.org/snp2019/

Fluidity of quark-gluon plasma (QGP) is studied where interaction between quark and gluon is mapped through fugacity in particle distribution function using lattice quantum chromodynamics (LQCD) results., Comment: Conference proceeding in 64th DAE-BRNS Symposium on Nuclear Physics, Link- http://sympnp.org/snp2019/

Using density functional theory, we investigate the interplay between the stacking order and sequence of bilayers composed of an Fe and a Rh layer on the Re(0001) and their magnetic properties. We find that fcc/ffc stacked bilayers are energetically very unfavorable, while all other combinations of hcp and fcc stacking are energetically close. The magnetic interactions are evaluated by mapping the DFT total energies onto a spin model, which contains Heisenberg exchange, Dzyaloshinskii-Moriya interaction, the magnetocrystalline anisotropy energy, and higher-order exchange interactions. We find that the stacking sequence of the bilayer significantly modifies the magnetic interactions. As a result, we find a DMI driven cycloidal spin spiral ground state with a period of 11~nm for hcp-Fe/hcp-Rh. For fcc-Fe/hcp-Rh and hcp-Fe/fcc-Rh, we obtain a ferromagnetic ground state. The spin spiral energy dispersion of hcp-Fe/hcp-Rh including spin-orbit coupling suggests that isolated skyrmions can be stabilized in the field-polarized ferromagnetic background at external magnetic fields. If the Fe layer is sandwiched between the Rh overlayer and the Re(0001) substrate, there is a competition between the ferromagnetic coupling preferred by the Rh-Fe hybridization and the antiferromagnetic coupling induced by the Fe-Re hybridization. Due to the Fe/Re interface the DMI can become very large. For fcc-Rh/hcp-Fe, we obtain a cycloidal spin spiral with a period of 1.7~nm which is induced by frustration of exchange interactions and further stabilized by the DMI. For hcp-Rh/hcp-Fe, we find a DMI driven cycloidal spin spiral with a period of 4~nm and locally nearly antiparallel magnetic moments due to antiferromagnetic nearest-neighbor exchange. The higher-order exchange constants can be significant in the considered films, however, they do not stabilize multi-$Q$ states.

Transition-metal interfaces and multilayers are a very promising class of systems to realize nanometer-sized, stable magnetic skyrmions for future spintronic devices. For room temperature applications it is crucial to understand the interactions which control the stability of isolated skyrmions. Typically, skyrmion properties are explained by the interplay of pair-wise exchange interactions, the Dzyaloshinskii-Moriya interaction and the magnetocrystalline anisotropy energy. Here, we demonstrate that higher-order exchange interactions -- which have so far been neglected -- can play a key role for the stability of skyrmions. We use an atomistic spin model parametrized from first-principles and compare three different ultrathin film systems. We consider all fourth order exchange interactions and show that in particular the four-site four spin interaction has a giant effect on the energy barrier preventing skyrmion and antiskyrmion collapse into the ferromagnetic state. Our work opens new perspectives to enhance the stability of topological spin structures.

We have attempted to build a parametric based simplified and analytical model to map the interaction of quarks and gluons in presence of magnetic field, which has been constrained by quark condensate and thermodynamical quantities like pressure, energy density etc., obtained from the calculation of lattice quantum chromodynamics. To fulfill that mapping, we have assumed a parametric temperature and magnetic field dependent degeneracy factor, average energy, momentum and velocity of quarks and gluons. Implementing this QCD interaction in calculation of transport coefficient at finite magnetic field, we have noticed that magnetic field and interaction both are two dominating sources, for which the values of transport coefficients can be reduced. Though the methodology is not so robust, but with the help of its simple parametric expressions, one can get a quick rough estimation of any phenomenological quantity, influenced by temperature and magnetic field dependent QCD interaction., Comment: Accepted in IJMPE

We have attempted to build first some simplified model to map the interaction of quarks and gluons, which can be contained by their thermodynamical quantity like entropy density, obtained from calculation of lattice quantum chromo dynamics (LQCD). With respect to entropy density of the standard non-interacting massless quark gluon plasma (QGP), its interacting values from LQCD simulation are reduced as we go from higher to lower temperature through the cross-over of quark-hadron phase transition. By parameterizing increasing degeneracy factor or increasing interaction-fugacity or decreasing thermal width of quarks and gluons with temperature, we have matched LQCD data.Using that interaction picture, shear viscosity and electrical conductivity are calculated. For getting nearly perfect fluid nature of QGP, interaction might have some role when we consider temperature dependent thermal width., Comment: 17 pages, 5 figures

Here, we present the quantum version of a very famous statistical decision problem, whose classical version is counter-intuitive to many. The Monty Hall game can be phrased as a two person game between Alice and Bob. In their pioneering work, Flitney and Abbott [Phys. Rev. A 65, 062318 (2002)] showed that by using a maximally entangled system for Alice and Bob's choices, and using quantum strategies, Bob and Alice can win or lose depending on the strategy chosen by either of the players. Here we develop a new quantum algorithm with quantum circuits for playing the quantum Monty Hall game by a user. Our quantum algorithm uses the quantum principles of superposition and entanglement so that it can be efficiently played on a quantum computer. We present two schemes, one calculating the probability of winning or loss and the other determining whether a player (say Alice) wins or not., Comment: 7 pages, 3 figures