146 citations · 1.3k across the 24 of their papers we have counts for
25 papers
Designs without disorder: unitary -designs from a single-site bulk defect
Samudra Sur, Pratik Nandy
We show that an local defect is sufficient to generate approximate unitary -designs from an otherwise integrable quantum many-body system. Using a two-Pauli-kick (2PK) pr…
Unitary -designs without independent Hamiltonian quenches
Pratik Nandy
Unitary -designs provide a resource-efficient framework for emulating Haar randomness up to the -th order. Quench-based protocols have recently been shown to generate such de…
Krylov Complexity Under Hamiltonian Deformations and Toda Flows
Kazutaka Takahashi, Pratik Nandy, Adolfo del Campo
The quantum dynamics of a complex system can be efficiently described in Krylov space, the minimal subspace in which the dynamics unfolds. We apply the Krylov subspace method for H…
Complexity of Quadratic Quantum Chaos
Pallab Basu, Suman Das, Pratik Nandy
We investigate minimal two-body Hamiltonians with random interactions that generate spectra resembling those of Gaussian random matrices, a phenomenon we term quadratic quantum cha…
Free Probability approach to spectral and operator statistics in Rosenzweig-Porter random matrix ensembles
Viktor Jahnke, Pratik Nandy, Kuntal Pal +2
Utilizing the framework of free probability, we analyze the spectral and operator statistics of the Rosenzweig-Porter random matrix ensembles, which exhibit a rich phase structure…
Krylov space approach to Singular Value Decomposition in non-Hermitian systems
Pratik Nandy, Tanay Pathak, Zhuo-Yu Xian +1
We propose a tridiagonalization approach for non-Hermitian random matrices and Hamiltonians using singular value decomposition (SVD). This technique leverages the real and non-nega…
Tridiagonal Hamiltonians modeling the density of states of the Double-Scaled SYK model
Pratik Nandy
By analyzing the global density of states (DOS) in the Double-Scaled Sachdev-Ye-Kitaev (DSSYK) model, we construct a finite-dimensional Hamiltonian that replicates this DOS. We the…
Krylov fractality and complexity in generic random matrix ensembles
Budhaditya Bhattacharjee, Pratik Nandy
Krylov space methods provide an efficient framework for analyzing the dynamical aspects of quantum systems, with tridiagonal matrices playing a key role. Despite their importance,…
Probing quantum chaos through singular-value correlations in sparse non-Hermitian SYK model
Pratik Nandy, Tanay Pathak, Masaki Tezuka
Utilizing singular value decomposition, our investigation focuses on the spectrum of the singular values within a sparse non-Hermitian Sachdev-Ye-Kitaev (SYK) model. Unlike the com…
Quantum Dynamics in Krylov Space: Methods and Applications
Pratik Nandy, Apollonas S. Matsoukas-Roubeas, Pablo Martínez-Azcona +2
The dynamics of quantum systems unfolds within a subspace of the state space or operator space, known as the Krylov space. This review presents the use of Krylov subspace methods t…
Operator dynamics in Lindbladian SYK: a Krylov complexity perspective
Budhaditya Bhattacharjee, Pratik Nandy, Tanay Pathak
We use Krylov complexity to study operator growth in the -body dissipative SYK model, where the dissipation is modeled by linear and random -body Lindblad operators. In the l…
On Krylov complexity in open systems: an approach via bi-Lanczos algorithm
Aranya Bhattacharya, Pratik Nandy, Pingal Pratyush Nath +1
Continuing the previous initiatives arXiv: 2207.05347 and arXiv: 2212.06180, we pursue the exploration of operator growth and Krylov complexity in dissipative open quantum systems.…
Operator growth in open quantum systems: lessons from the dissipative SYK
Budhaditya Bhattacharjee, Xiangyu Cao, Pratik Nandy +1
We study the operator growth in open quantum systems with dephasing dissipation terms, extending the Krylov complexity formalism of Phys. Rev. X 9, 041017. Our results are based on…
Krylov complexity in large- and double-scaled SYK model
Budhaditya Bhattacharjee, Pratik Nandy, Tanay Pathak
Considering the large- expansion of the Sachdev-Ye-Kitaev (SYK) model in the two-stage limit, we compute the Lanczos coefficients, Krylov complexity, and the higher Krylov cumul…
Probing quantum scars and weak ergodicity-breaking through quantum complexity
Budhaditya Bhattacharjee, Samudra Sur, Pratik Nandy
Scar states are special many-body eigenstates that weakly violate the eigenstate thermalization hypothesis (ETH). Using the explicit formalism of the Lanczos algorithm, usually kno…
Operator growth and Krylov construction in dissipative open quantum systems
Aranya Bhattacharya, Pratik Nandy, Pingal Pratyush Nath +1
Inspired by the universal operator growth hypothesis, we extend the formalism of Krylov construction in dissipative open quantum systems connected to a Markovian bath. Our construc…
Krylov complexity in saddle-dominated scrambling
Budhaditya Bhattacharjee, Xiangyu Cao, Pratik Nandy +1
In semi-classical systems, the exponential growth of the out-of-timeorder correlator (OTOC) is believed to be the hallmark of quantum chaos. However,on several occasions, it has be…
Balanced Partial Entanglement and Mixed State Correlations
Hugo A. Camargo, Pratik Nandy, Qiang Wen +1
Recently in Ref.\cite{Wen:2021qgx}, one of the authors introduced the balanced partial entanglement (BPE), which has been proposed to be dual to the entanglement wedge cross-sectio…
Q-curvature and Path Integral Complexity
Hugo A. Camargo, Pawel Caputa, Pratik Nandy
We discuss the interpretation of path integral optimization as a uniformization problem in even dimensions. This perspective allows for a systematical construction of the higher-di…
Bath deformations, islands and holographic complexity
Aranya Bhattacharya, Arpan Bhattacharyya, Pratik Nandy +1
Considering a doubly holographic model, we study the evolution of holographic subregion complexity corresponding to deformations of bath state by a relevant scalar operator, which…
Partial islands and subregion complexity in geometric secret-sharing model
Aranya Bhattacharya, Arpan Bhattacharyya, Pratik Nandy +1
We compute the holographic subregion complexity of a radiation subsystem in a geometric secret-sharing model of Hawking radiation in the "complexity = volume" proposal. The model i…
Eigenstate capacity and Page curve in fermionic Gaussian states
Budhaditya Bhattacharjee, Pratik Nandy, Tanay Pathak
Capacity of entanglement (CoE), an information-theoretic measure of entanglement, defined as the variance of modular Hamiltonian, is known to capture the deviation from the maximal…
Capacity of Entanglement in Local Operators
Pratik Nandy
We study the time evolution of the excess value of capacity of entanglement between a locally excited state and ground state in free, massless fermionic theory and free Yang-Mills…
Islands and complexity of eternal black hole and radiation subsystems for a doubly holographic model
Aranya Bhattacharya, Arpan Bhattacharyya, Pratik Nandy +1
We study the entanglement islands and subsystem volume complexity corresponding to the left/ right entanglement of a conformal defect in -dimensions in Randall-Sundrum (RS) bran…