19 citations · 46 across the 6 of their papers we have counts for
6 papers
Recursion method for quench dynamics: strengths and limitations
Ilya Shirokov, Viacheslav Khrushchev, Filipp Uskov +3
The recursion method, which solves coupled Heisenberg equations in a Lanczos operator basis, has recently emerged as a powerful nonperturbative tool for computing dynamical correla…
Pseudomode expansion of many-body correlation functions
Alexander Teretenkov, Filipp Uskov, Oleg Lychkovskiy
We present an expansion of a many-body correlation function in a sum of pseudomodes -- exponents with complex frequencies that encompass both decay and oscillations. The pseudomode…
Quantum dynamics in one and two dimensions via recursion method
Filipp Uskov, Oleg Lychkovskiy
We report an implementation of the recursion method that addresses quantum many-body dynamics in the nonperturbative regime. The method essentially amounts to constructing a Lanczo…
A variational lower bound on the ground state of a many-body system and the squaring parametrization of density matrices
F. Uskov, O. Lychkovskiy
A variational upper bound on the ground state energy of a quantum system, , is well-known (here is the Hamiltonian of t…
Merits of using density matrices instead of wave functions in the stationary Schrödinger equation for systems with symmetries
E. Shpagina, F. Uskov, N. Il'in +1
The stationary Schrödinger equation can be cast in the form , where is the system's Hamiltonian and is the system's density matrix. We explore the merits of this…
Squaring parametrization of constrained and unconstrained sets of quantum states
N. Il'in, E. Shpagina, F. Uskov +1
A mixed quantum state is represented by a Hermitian positive semi-definite operator with unit trace. The positivity requirement is responsible for a highly nontrivial geometry…