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C. C. Korikov

Publications and source records attributed to C. C. Korikov.

8 recordsLinked to original sources

SVD Contextual Sparsity Predictors for Fast LLM Inference

Contextual sparsity is one of the approaches used to reduce computational complexity in the inference process of large language models (LLMs). Existing techniques for efficient LLM inference acceleration based on contextual sparsity with minimal accuracy degradation require training sparse pattern predictors. This paper presents a framework for accelerating inference of ReGLU-based feed-forward networks (FFNs) within LLMs. The proposed framework provides a fast, training-free method for building sparse pattern predictors using truncation-aware singular value decomposition (SVD) of the gate projection matrix, along with a threshold calibration algorithm, and inference executors supporting conditional computation on CUDA and CANN devices. Experiments on three sparse LLMs with an average activation sparsity level of 90% in the FFNs demonstrate up to a 1.8x reduction in end-to-end decoding time while maintaining less than 1% degradation in benchmark scores on tasks involving complex math and code generation. This work advances the deployment of LLMs on edge devices.

cs.LG↗

Why the Casimir Force for Magnetic Metals Computed by the Lifshitz Theory Using the Drude Model Disagrees with the Measurement Data

We consider the Casimir force in configurations with magnetic metal plates and analyze the reasons why the predictions of the Lifshitz theory using the dielectric permittivity of the Drude model are inconsistent with the measurement data. For this purpose, the contributions of the electromagnetic waves with the transverse magnetic and transverse electric polarizations to the Casimir force are computed using the Lifshitz theory expressed in terms of the pure imaginary Matsubara frequencies. Furthermore, the fractions of the evanescent and propagating waves in these contributions are found using an equivalent formulation of the Lifshitz theory along the real frequency axis. All computations are performed for Au-Ni and Ni-Ni plates using the Drude model and the experimentally consistent plasma model over the separation region from 0.5 to 6~mum, where the total force value is determined by conduction electrons. It is shown that the transverse magnetic contribution to the Casimir force does not depend on the used model of the dielectric permittivity, so that the total difference between the predictions of the Lifshitz theory using the Drude model and the measurement data is determined by the transverse electric contribution. In doing so, as opposed to the case of nonmagnetic metals, both fractions of the evanescent and propagating waves in this contribution depend on the model of the dielectric permittivity used in computations, whereas the magnetic properties of the plate metal influence the Casimir force solely through the fraction of propagating waves in the transverse electric contribution. The issue of a more adequate theoretical description of the electromagnetic response of magnetic metals is discussed.

quant-ph↗

Nonequilibrium Casimir pressure for two graphene-coated plates: Quantum field theoretical approach

We consider the nonequilibrium Casimir pressure in the system of two parallel graphene-coated plates one of which is either warmer or cooler than the environment. The electromagnetic response of graphene coating characterized by the nonzero energy gap and chemical potential is described in the framework of the Dirac model by means of the polarization tensor. It is shown that the magnitude of the nonequilibrium Casimir pressure on a warmer plate than the environment is larger and on a cooler plate is smaller than the magnitude of the standard Casimir pressure in the state of thermal equilibrium. According to our results, the spatially local theory underestimates the role of the effects of nonequilibrium. This underestimation increases for asmaller chemical potential of the graphene coating and at lower temperatures of the cooled plate. Possible applications of the obtained results are discussed.

quant-ph↗

Polarization tensor in spacetime of three dimensions and quantum field theoretical description of the nonequilibrium Casimir force in graphene systems

The polarization tensor of graphene derived in the framework of the Dirac model using the methods of thermal quantum field theory in (2+1) dimensions is recast in a mathematically equivalent but more compact and convenient in computations form along the real frequency axis. The obtained unified expressions for the components of the polarization tensor are equally applicable in the regions of the on- and off-the-mass-shell electromagnetic waves. The advantages of the presented formalism are demonstrated on the example of nonequilibrium Casimir force in the configuration of two parallel graphene-coated dielectric plates one of which is either hotter or colder than the environment. This force is investigated as a function of temperature, the energy gap, and chemical potential of graphene coatings with account of the effects of spatial dispersion. Besides the thermodynamically nonequilibrium Casimir and Casimir-Polder forces, the obtained form of the polarization tensor can be useful for investigation of many diverse physical phenomena in graphene systems, such as surface plasmons, reflectances, electrical conductivity, radiation heat transfer, etc.

quant-ph↗

Nernst heat theorem for the Casimir-Polder interaction between a magnetizable atom and ferromagnetic dielectric plate

We find the low-temperature behavior of the Casimir-Polder free energy for a polarizable and magnetizable atom interacting with a plate made of ferromagnetic dielectric material. It is shown that the corresponding Casimir-Polder entropy goes to zero with vanishing temperature, i.e., the Nernst heat theorem is satisfied, if the dc conductivity of the plate material is disregarded in calculations. If the dc conductivity is taken into account, the Nernst theorem is violated. These results are discussed in light of recent experiments.

quant-ph↗

Theory of reflectivity properties of graphene-coated material plates

The theoretical description for the reflectivity properties of dielectric, metal and semiconductor plates coated with graphene is developed in the framework of the Dirac model. Graphene is described by the polarization tensor allowing the analytic continuation to the real frequency axis. The plate materials are described by the frequency-dependent dielectric permittivities. The general formulas for the reflection coefficients and reflectivities of the graphene-coated plates, as well as their asymptotic expressions at high and low frequencies, are derived. The developed theory is applied to the graphene-coated dielectric (fused silica), metal (Au and Ni), and semiconductor (Si with various charge carrier concentrations) plates. In all these cases the impact of graphene coating on the plate reflectivity properties is calculated over the wide frequency ranges. The obtained results can be used in many applications exploiting the graphene coatings, such as the optical detectors, transparent conductors, anti-reflection surfaces etc.

cond-mat.mtrl-sci↗

Analytic results for the Casimir free energy between ferromagnetic metals

We derive perturbation analytic expressions for the Casimir free energy and entropy between two dissimilar ferromagnetic plates which are applicale at arbitrarily low temperature. The dielectric properties of metals are described using either the nondissipative plasma model or the Drude model taking into account the dissipation of free charge carriers. Both cases of constant and frequency-dependent magnetic permeability are considered. It is shown that for ferromagnetic metals described by the plasma model the Casimir entropy goes to zero when the temperature vanishes, i.e., the Nernst heat theorem is satisfied. For ferromagnetic metals with perfect crystal lattices described by the Drude model the Casimir entropy goes to a nonzero constant depending on the parameters of a system with vanishing temperature, i.e., the Nernst heat theorem is violated. This constant can be positive which is quite different from the earlier investigated case of two nonmagnetic metals.

quant-ph↗

Casimir entropy for magnetodielectrics

We find the analytic expressions for the Casimir free energy, entropy and pressure at low temperature in the configuration of two parallel plates made of magnetodielectic material. The cases of constant and frequency-dependent dielectic permittivity and magnetic permeability of the plates are considered. Special attention is paid to the account of dc conductivity. It is shown that in the case of finite static dielectric permittivity and magnetic permeability the Nernst heat theorem for the Casimir entropy is satisfied. If the dc conductivity is taken into account, the Casimir entropy goes to a positive nonzero limit depending on the parameters of a system when the temperature vanishes, i.e., the Nernst theorem is violated. The experimental situation is also discussed.

quant-ph↗