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A. Gorsky

Publications and source records attributed to A. Gorsky.

At least 19 recordsLinked to original sources
arXiv2022

Dualities in quantum integrable many-body systems and integrable probabilities -- I

In this study we map the dualities observed in the framework of integrable probabilities into the dualities familiar in a realm of integrable many-body systems. The dualities between the pairs of stochastic processes involve one representative from Macdonald-Schur family, while the second representative is from stochastic higher spin six-vertex model of TASEP family. We argue that these dualities are counterparts and generalizations of the familiar quantum-quantum (QQ) dualities between pairs of integrable systems. One integrable system from QQ dual pair belongs to the family of inhomogeneous XXZ spin chains, while the second to the Calogero-Moser-Ruijsenaars-Schneider (CM-RS) family. The wave functions of the Hamiltonian system from CM-RS family are known to be related to solutions to (q)KZ equations at the inhomogeneous spin chain side. When the wave function gets substituted by the measure, bilinear in wave functions, a similar correspondence holds true. As an example, we have elaborated in some details a new duality between the discrete-time inhomogeneous multispecies TASEP model on the circle and the quantum Goldfish model from the RS family. We present the precise map of the inhomogeneous multispecies TASEP and 5-vertex model to the trigonometric and rational Goldfish models respectively, where the TASEP local jump rates get identified as the coordinates in the Goldfish model. Some comments concerning the relation of dualities in the stochastic processes with the dualities in SUSY gauge models with surface operators included are made.

math-ph↗
arXiv2021

Mobility Edge in the Anderson model on partially disordered random regular graphs

In this Letter we study numerically the Anderson model on partially disordered random regular graphs (RRG) considered as the toy model for a Hilbert space of interacting disordered many-body system. The protected subsector of zero-energy states in a many-body system corresponds to clean nodes in RRG ensemble. Using adjacent gap ratio statistics and IPR we find the sharp mobility edge in the spectrum of one-particle Anderson model above some critical density of clean nodes. Its position in the spectrum is almost independent on the disorder strength. The possible application of our result for the controversial issue of mobility edge in the many-body localized (MBL) phase is discussed.

cond-mat.dis-nn↗
arXiv2021

$T\bar{T}$-deformed 2D Yang-Mills at large N: collective field theory and phase transitions

We consider the $T\bar T$ deformation of 2d large $N$ YM theory on a cylinder, sphere and disk. The collective field theory Hamiltonian for the deformed theory is derived and the particular solutions to the equations of motion of the collective theory are found for the sphere. The account of the non-perturbative branch of the solution amounts to the first-order phase transition at the $(A,τ)$ plane. We analyze the third-order phase transition in the deformed theory on the disk and derive the critical area as a function of the boundary holonomy. A kind of Hagedorn behavior in the spectral density is discussed.

hep-th↗
arXiv2020

Non-backtracking walks reveal compartments in sparse chromatin interaction networks

Chromatin communities stabilized by protein machinery play essential role in gene regulation and refine global polymeric folding of the chromatin fiber. However, treatment of these communities in the framework of the classical network theory (stochastic block model, SBM) does not take into account intrinsic linear connectivity of the chromatin loci. Here we propose the "polymer" block model, paving the way for community detection in polymer networks. On the basis of this new model we modify the non-backtracking flow operator and suggest the first protocol for annotation of compartmental domains in sparse single cell Hi-C matrices. In particular, we prove that our approach corresponds to the maximum entropy principle. The benchmark analyses demonstrates that the spectrum of the polymer non-backtracking operator resolves the true compartmental structure up to the theoretical detectability threshold, while all commonly used operators fail above it. We test various operators on real data and conclude that the sizes of the non-backtracking single cell domains are most close to the sizes of compartments from the population data. Moreover, the found domains clearly segregate in the gene density and correlate with the population compartmental mask, corroborating biological significance of our annotation of the chromatin compartmental domains in single cells Hi-C matrices.

q-bio.MN↗
arXiv2020

Self-isolation or borders closing: what prevents epidemic spreading better?

Pandemic distribution of COVID-19 in the world has motivated us to discuss combined effects of network clustering and adaptivity on epidemic spreading. We address the question concerning the choice of optimal mechanism for most effective prohibiting disease propagation in a connected network: adaptive clustering, which mimics self-isolation (SI) in local communities, or sharp instant clustering, which looks like frontiers closing (FC) between cities and countries. SI-networks are "adaptively grown" under condition of maximization of small cliques in the entire network, while FC-networks are "instantly created". Running the standard SIR model on clustered SI- and FC-networks, we demonstrate that the adaptive network clustering prohibits the epidemic spreading better than the instant clustering in the network with similar parameters. We found that SI model has scale-free property for degree distribution $P(k)\sim k^η$ with small critical exponent $-2<η<-1$ and argue that scale-free behavior emerges due to the randomness in the initial degree distributions and is absent for random regular graphs.

physics.soc-ph↗
arXiv2019

Dynamics of non-Abelian strings in the theory interpolating from ${\mathcal N}=2$ to ${\mathcal N}=1$ supersymmetric QCD

We study the dynamics of non-Abelian vortex strings supported in ${\mathcal N}=2$ supersymmetric QCD with the U$(N)$ gauge group and $N_f=N$ quark flavors deformed by the mass $μ$ of the adjoint matter. In the limit of large $μ$ the bulk four-dimensional theory flows to ${\mathcal N}=1$ supersymmetric QCD. The dynamics of orientational zero modes of the non-Abelian string is described by the world sheet CP$(N-1)$ model. At $μ=0$ this model has ${\mathcal N}= \left(2,2\right) $ supersymmetry while at large $μ$ it flows to the non-supersymmetric CP$(N-1)$ model. We solve the world sheet model in the large $N$ approximation and find a rich phase structure with respect to the deformation parameter $μ$ and quark mass differences. The phases include two strong coupling phases and two Higgs phases. In particular, the Higgs phase at small $μ$ supports CP$(N-1)$ model kinks representing confined monopoles of the bulk QCD, while in the large-$μ$ Higgs phase monopoles disappear.

hep-th↗
arXiv2019

Metal or Insulator? Dirac operator spectrum in holographic QCD

The lattice studies in QCD demonstrate the nontrivial localization behavior of the eigenmodes of the 4D Euclidean Dirac operator considered as Hamiltonian of $4+1$ dimensional disordered system. We use the holographic viewpoint to provide the conjectural explanation of these properties. The delocalization of all modes in the confined phase is related to the $θ=π$ - like phenomena when the domain walls between degenerated vacua are possible. It is conjectured that the localized modes separated by mobility edge from the rest of the spectrum in deconfined QCD correspond to the near-horizon region in the holographic dual.

hep-th↗
arXiv2019

Finite-size effects in exponential random graphs and cluster evaporation

In this Letter we find numerically the strong finite-size effects in the critical behavior of Erdős-Rényi (ER) networks supplemented with chemical potentials for some motifs, in particular 2-stars and triangles. For the 2-star model above the critical value of the chemical potential a ground state looks as star-like graph with the finite set of hubs at ER parameter $p<0.5$ or as the single cluster at $p>0.5$. It is found that there exists the critical value of number of nodes $N^{*}(p)$ when the ground state undergoes clear-cut crossover and at $N>N^{*}(p)$ the network flows via a cluster evaporation to the state involving the small star in the ER environment. The similar evaporation of the cluster takes place at $N>N^{*}(p)$ in the Strauss model. We suggest that the entropic trap mechanism is relevant for microscopic mechanism behind the crossover regime. The possible analogies concerning the strong entropic finite-size effects in the holographic description of matrix black hole (BH) formation and evaporation are mentioned.

cond-mat.dis-nn↗
arXiv2018

Spectral peculiarity and criticality of the human connectome

We have performed the comparative spectral analysis of structural connectomes for various organisms using open-access data. Our analysis indicates several new peculiar features of the human connectome. We found that the spectral density of human connectome has the maximal deviation from the spectral density of the randomized network compared to all other organisms. For many animals except human structural peculiarities of connectomes are well reproduced in the network evolution induced by the preference of 3-cycles formation. To get the reliable fit , we discovered the crucial role of the conservation of local clusterization in human connectome evolution. We investigated for the first time the level spacing distribution in the spectrum of human connectome graph Laplacian. It turns out that the spectral statistics of human connectome corresponds exactly to the critical regime familiar in the condensed matter physics which is hybrid of Wigner-Dyson and Poisson distributions. This observation provides the strong support for the much debated statement of the brain criticality.

q-bio.NC↗
arXiv2018

On instability of ground states in 2D CP(N-1) and O(N) models at large N

We consider properties of the inhomogeneous solution found recently for \mbox{$\mathbb{CP}^{\,N-1}$} model. The solution was interpreted as a soliton. We reevaluate its energy in three different ways and find that it is negative contrary to the previous claims. Hence, instead of the solitonic interpretation it calls for reconsideration of the issue of the true ground state. While complete resolution is still absent we show that the energy density of the periodic elliptic solution is lower than the energy density of the homogeneous ground state. We also discuss similar solutions for the ${\mathbb{O}}(N)$ model and for SUSY extensions.

hep-th↗
arXiv2018

Phase transitions in social networks inspired by the Schelling model

We propose two models of social segregation inspired by the Schelling model. Agents in our models are nodes of evolving social networks. The total number of social connections of each node remains constant in time, though may vary from one node to the other. The first model describes a "polychromatic" society, in which colors designate different social categories of agents. The parameter $μ$ favors/disfavors connected "monochromatic triads", i.e. connected groups of three individuals \emph{within the same social category}, while the parameter $ν$ controls the preference of interactions between two individuals \emph{from different social categories}. The polychromatic model has several distinct regimes in $(μ,ν)$-parameter space. In $ν$-dominated region, the phase diagram is characterized by the plateau in the number of the inter-color connections, where the network is bipartite, while in $μ$-dominated region, the network looks as two weakly connected unicolor clusters. At $μ>μ_{crit}$ and $ν>ν_{crit}$ two phases are separated by a critical line, while at small values of $μ$ and $ν$, a gradual crossover between the two phases occurs. The second "colorless" model describes a society in which the advantage/disadvantage of forming small fully connected communities (short cycles or cliques in a graph) is controlled by a parameter $γ$. We analyze the topological structure of a social network in this model and demonstrate that above a critical threshold, $γ^+>0$, the entire network splits into a set of weakly connected clusters, while below another threshold, $γ^-<0$, the network acquires a bipartite graph structure. Our results propose mechanisms of formation of self-organized communities in international communication between countries, as well as in crime clans and prehistoric societies.

physics.soc-ph↗
arXiv2018

Mobility edge and Black Hole Horizon

We conjecture that the mobility edge in the 4D Euclidean Dirac operator spectrum in QCD in the deconfined phase found in the lattice studies corresponds to the near black hole (BH) horizon region in the holographic dual. We present some evidences both from the field theory side and from the worldsheet theory of long open string.

hep-th↗
arXiv2018

Bands and gaps in Nekrasov partition function

We discuss the effective twisted superpotentials of 2d $\mathcal{N}=(2,2)$ theories arising upon the reduction of 4d $\mathcal{N}=2$ gauge theories on the $Ω$-deformed cigar-like geometry. We explain field-theoretic origins of the gaps in the spectrum in the corresponding quantum mechanical (QM) systems. We find local 2d descriptions of the physics near these gaps by resumming the non-perturbative part of the twisted superpotential and discuss arising wall-crossing phenomena. The interpretation of the associated phenomena in the classical Liouville theory and in the scattering of two heavy states in $AdS_3$ gravity is suggested. Some comments concerning a possible interpretation of the band structure in QM in terms of the Schwinger monopole-pair production in 4d are presented.

hep-th↗
arXiv2018

Many-body localization and new critical phenomena in regular random graphs and constrained Erdős-Renyi networks

We consider from the localization perspective the new critical phenomena discovered recently for perturbed random regular graphs (RRG) and constrained Erdős-Rényi networks (CERN) \cite{crit2}. At some critical value of the chemical potential of 3-cycles, $μ$, the network decays into the maximally possible number of almost full subgraphs, and the spectrum of the Laplacian matrix acquires the two-zonal structure with a large gap. We find that the Laplacian eigenvalue statistics corresponds to delocalized states in one zone, and to the localized states in the second one. We interpret this behavior in terms of the many-body localization problem where the structure of the Fock space of some interacting many-body system is approximated by the RGG and/or by the CERN. We associate 3-cycles in RRGs and CERNs as resonant triples in the Fock space. We show that the scenario of the "localization without disorder", discussed previously in physical space, can be realized in the Fock space as well. We argue that it is natural to identify clusters in a RRG with particles in a many-body system above the phase transition. We discuss the controversial issue of an additional phase transition between ergodic and non-ergodic regimes in the delocalized phase in the Fock space and find a strong "memory dependence" of the states in the delocalized phase, thus advocating existence of non-ergodic delocalized states.

cond-mat.dis-nn↗
arXiv2017

On magnetic and vortical susceptibilities of the Cooper condensate

We discuss the susceptibility of the Cooper condensate in the s-wave $2+1$ superconductor in the external magnetic field and in the rotating frame. The extended holographic model involving the charged rank-two field is considered and it is argued that the susceptibility does not vanish. We interpret non-vanishing susceptibilities as the admixture of the p-wave triplet component in the Cooper condensate in the external field.

cond-mat.supr-con↗
arXiv2017

Chiral heat wave in cold Fermi liquid and modified zero sound

We discuss kinetic equations involving the anomalous terms responsible for the chiral anomaly. The general chiral heat wave in cold Fermi liquid is described and the modification of the anomalous zero sound at small temperature and vorticity is found.

hep-th↗
arXiv2017

Surface defects and instanton-vortex interaction

We propose a simple formula for the 4d-2d partition function of half-BPS surface defects in $d=4,\ \mathcal{N}=2$ gauge theories: $Z^{\text{4d-2d}}=\langle Z^{\text{2d}} \rangle_{\text{4d}}$. Our results are applicable for any surface defect obtained by gauging a 2d flavour symmetry using a 4d gauge group. For defects obtained via the Higgsing procedure, our formula reproduces the recent calculation by Pan and Peelaers. For Gukov-Witten defects our results reproduce the orbifold calculation by Kanno and Tachikawa. We emphasize the role of "negative vortices" which are realized as negative D0 branes.

hep-th↗