A5051926665- Quantum many-body systems
- Quantum and electron transport phenomena
- Physics of Superconductivity and Magnetism
- Quantum Computing Algorithms and Architecture
- Cold Atom Physics and Bose-Einstein Condensates
- Theoretical and Computational Physics
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Opinion Dynamics and Social Influence
- Advanced Thermodynamics and Statistical Mechanics
- Quantum, superfluid, helium dynamics
- Spectroscopy and Quantum Chemical Studies
- Quantum Information and Cryptography
- Magnetism in coordination complexes
- Magnetic properties of thin films
- Quantum Mechanics and Applications
- Lanthanide and Transition Metal Complexes
- Neural Networks and Reservoir Computing
- Quantum chaos and dynamical systems
- Computational Physics and Python Applications
- Topological Materials and Phenomena
- Crystallography and molecular interactions
- Magneto-Optical Properties and Applications
- Metal-Organic Frameworks: Synthesis and Applications
- Electron Spin Resonance Studies
Jagiellonian University
2016-2025
Institute of Physics
2007-2020
Vienna Center for Quantum Science and Technology
2012-2015
University of Vienna
2012-2015
Los Alamos National Laboratory
2007-2012
Institute of Photonic Sciences
2010
The dynamics of a quantum phase transition is inextricably woven with the formation excitations, as result critical slowing down in neighborhood point. We design transitionless driving through point that allows one to access ground state broken-symmetry by finite-rate quench control parameter. method illustrated one-dimensional Ising model transverse field. Driving assisted an auxiliary Hamiltonian, for which interplay between range interaction and modes where excitations are suppressed elucidated.
Quantum computers hold the promise of solving certain problems that lie beyond reach conventional computers. Establishing this capability, especially for impactful and meaningful problems, remains a central challenge. Here we show superconducting quantum annealing processors can rapidly generate samples in close agreement with solutions Schrödinger equation. We demonstrate area-law scaling entanglement model quench dynamics two-, three- infinite-dimensional spin glasses, supporting observed...
We present an open-source tensor network Python library for quantum many-body simulations. At its core is Abelian-symmetric tensor, implemented as a sparse block structure managed by logical layer on top of dense multidimensional array backend. This serves the basis higher-level algorithms operating matrix product states and projected entangled pair states. An appropriate backend, such PyTorch, gives direct access to automatic differentiation (AD) cost-function gradient calculations...
We present an open-source tensor network Python library for quantum many-body simulations. At its core is Abelian-symmetric tensor, implemented as a sparse block structure managed by logical layer on top of dense multidimensional array backend. This serves the basis higher-level algorithms operating matrix product states and projected entangled pair states. An appropriate backend, such PyTorch, gives direct access to automatic differentiation (AD) cost-function gradient calculations...
Quantum Ising model in one dimension is an exactly solvable example of a quantum phase transition. We investigate its behavior during quench caused by gradual turning off the transverse bias field. The system then driven at fixed rate characterized time ${\ensuremath{\tau}}_{Q}$ across critical point from paramagnetic to ferromagnetic phase. In agreement with Kibble-Zurek mechanism (which recognizes that evolution approximately adiabatic far away, but becomes impulse sufficiently near...
Contrary to claims that a fundamental limit of precision in quantum metrology can be broken certain circumstances, new analysis shows this is not the case once one takes into account time needed perform operations.
Tensor networks are a powerful tool for studying emergent behavior in physical systems, but they often fail at predicting nonlocal properties. A new procedure demonstrates precisely how to extract that information.
The quantum Kibble-Zurek mechanism (QKZM) predicts universal dynamical behavior near the phase transitions (QPTs). It is now well understood for one-dimensional matter. Higher-dimensional systems, however, remain a challenge, complicated by fundamentally different character of associated QPTs and their underlying conformal field theories. In this work, we take first steps toward theoretical exploration QKZM in two dimensions interacting We study crossing QPT paradigmatic Ising model joint...
We propose a symmetric version of the multiscale entanglement renormalization ansatz in two spatial dimensions (2D) and use this to find an unknown ground state 2D quantum system. Results simple Ising model on $8\ifmmode\times\else\texttimes\fi{}8$ square lattice are found be very accurate even with smallest nontrivial truncation parameter.
We study quantum fidelity, the overlap between two ground states of a many-body system, focusing on thermodynamic regime. show how drop in fidelity near critical point encodes universal information about phase transition. Our general scaling results are illustrated Ising chain for which remarkably simple expression is found.
We investigate the relation between static correlation functions in ground state of local quantum many-body Hamiltonians and dispersion relations corresponding low energy excitations using formalism tensor network states. In particular, we show that Matrix Product State Transfer (MPS-TM) - a central object computation provides important information about location magnitude minima relation(s) present supporting numerical data for one-dimensional lattice continuum models as well...
The recognition that large classes of quantum many-body systems have limited entanglement in the ground and low-lying excited states led to dramatic advances their numerical simulation via so-called tensor networks. However, global dynamics elevates many particles into states, can lead macroscopic failure Here, we show for transport---one most important cases this failure---the fundamental issue is canonical basis which scenario cast: When flow through an interface, they scatter, generating...
A Gibbs operator ${e}^{\ensuremath{-}\ensuremath{\beta}H}$ for a two-dimensional (2D) lattice system with Hamiltonian $H$ can be represented by 3D tensor network, the third dimension being imaginary time (inverse temperature) $\ensuremath{\beta}$. Coarse graining network along $\ensuremath{\beta}$ results in 2D projected entangled-pair (PEPO) finite bond dimension. The coarse is performed tree of isometries. They are optimized variationally to maximize accuracy PEPO as representation thermal...
Abstract The cobalt(II) in [Co(NCS) 2 (4‐methoxypyridine) ] n are linked by pairs of thiocyanate anions into linear chains. In contrast to a previous structure determination, two crystallographically independent centers have been found be present. the antiferromagnetic state, below critical temperature ( T c =3.94 K) and field H =290 Oe), slow relaxations ferromagnetic chains observed. They originate mainly from defects magnetic structure, which has elucidated micromagnetic Monte Carlo...
Quantum computers hold the promise of solving certain problems that lie beyond reach conventional computers. Establishing this capability, especially for impactful and meaningful problems, remains a central challenge. One such problem is simulation nonequilibrium dynamics magnetic spin system quenched through quantum phase transition. State-of-the-art classical simulations demand resources grow exponentially with size. Here we show superconducting annealing processors can rapidly generate...
We derive an exact closed-form expression for fidelity susceptibility of even- and odd-sized quantum Ising chains in the transverse field. To this aim, we diagonalize Hamiltonian study gap between its positive negative parity subspaces. use it to identify ground state. point out misunderstanding some former studies discuss consequences. Last but not least, rigorously analyze properties gap. For example, analytical expressions showing exponential dependence on ratio system size correlation length.
The Kibble-Zurek mechanism predicts the formation of topological defects and other excitations that quantify how much a quantum system driven across critical point fails to be adiabatic. We out that, thanks divergent linear susceptibility at point, even tiny symmetry breaking bias can restore adiabaticity. minimal required scales like ${\ensuremath{\tau}}_{Q}^{\ensuremath{-}\ensuremath{\beta}\ensuremath{\delta}/(1+z\ensuremath{\nu})}$, where $\ensuremath{\beta}$, $\ensuremath{\delta}$, $z$,...
The Aubry-Andr\'e 1D lattice model describes a particle hopping in pseudo-random potential. Depending on its strength $\lambda$, all eigenstates are either localized ($\lambda>1$) or delocalized ($\lambda<1$). Near the transition, localization length diverges like $\xi\sim(\lambda-1)^{-\nu}$ with $\nu=1$. We show that when is initially prepared ground state and potential slowly ramped down across then -- analogy Kibble-Zurek mechanism it enters phase having finite...
A system gradually driven through a symmetry-breaking phase transition is subject to the Kibble-Zurek mechanism (KZM). As consequence of critical slowing down, its state cannot follow local equilibrium, and evolution becomes nonadiabatic near point. In simplest approximation, that stage can be regarded as an ``impulse'' where remains unchanged. It leads correct KZM scaling laws. However, such ``freeze-out'' might suggest coherence length nascent order parameter unchanged region traversed. By...
The two-dimensional infinite projected entangled pair states tensor network is evolved in imaginary time with the full update (FU) algorithm to simulate Shastry-Sutherland model a magnetic field at finite temperature directly thermodynamic limit. We focus on phase transition into $m=1/2$ magnetization plateau, which was observed experiments SrCu$_2$(BO$_3$)$_2$. For largest simulated bond dimension, early evolution high-temperature regime simple (SU) scheme and then, as correlation length...
This work introduces SpinGlassPEPS$.$jl, a software package implemented in Julia, designed to find low-energy configurations of generalized Potts models, including Ising and QUBO problems, utilizing heuristic tensor network contraction algorithms on quasi-2D geometries. In particular, the employs Projected Entangled-Pairs States approximate Boltzmann distribution corresponding model's cost function. enables an efficient branch-and-bound search (within probability space) that exploits...
We analyze the correlation between energy, momentum and spatial entanglement produced by two luminal jets in massive Schwinger model. Using tensor network methods, we show that for m/g > 1/{\pi}, vicinity of strong to weak coupling transition, a nearly perfect chargeless effective fluid behavior appears around mid-rapidity region with universal energy-pressure relationship. The evolution energy pressure is strongly correlated rise entropy, indicating key role quantum dynamics. Some these...
We introduce an inhomogeneous protocol to drive a weakly disordered quantum spin chain quasi-adiabatically across phase transition and minimize the residual energy of final state. The number spins that simultaneously reach critical point is controlled by length scale in which magnetic field modulated, introducing effective size favors adiabatic dynamics. dependence on this velocity at sweeps out shown be nonmonotonic. determine conditions for optimal suppression state show driving can...
We study ground-state fidelity defined as the overlap between two ground states of same quantum system obtained for slightly different values parameters its Hamiltonian. focus on thermodynamic regime $XY$ model and neighborhood critical points. describe extensively when it is dominated by universal contribution reflecting criticality phase transition. show that proximity to multicritical point leads anomalous scaling fidelity. also discuss in a characterized pronounced oscillations resulting...