30 citations · 85 across the 10 of their papers we have counts for
10 papers
Streamlined Krylov construction and classification of ergodic Floquet systems
Nikita Kolganov, Dmitrii A. Trunin
We generalize Krylov construction to periodically driven (Floquet) quantum systems using the theory of orthogonal polynomials on the unit circle. Compared to other approaches, our…
Unperturbation theory: reconstructing Lagrangians from instanton fluctuations
Farahmand Hasanov, Nikita Kolganov
Instantons present a deep insight into non-perturbative effects both in physics and mathematics. While leading instanton effects can be calculated simply as an exponent of the inst…
Nonequilibrium Schwinger-Keldysh formalism for density matrix states: analytic properties and implications in cosmology
Andrei O. Barvinsky, Nikita Kolganov
Motivated by cosmological Hartle-Hawking and microcanonical density matrix prescriptions for the quantum state of the Universe we develop Schwinger-Keldysh in-in formalism for gene…
Real-time diagram technique for instantonic systems
Nikita Kolganov
The Schwinger-Keldysh diagram technique is usually involved in the calculation of real-time in-in correlation functions. In the case of a thermal state, one can analytically contin…
Classical and quantum butterfly effect in nonlinear vector mechanics
Nikita Kolganov, Dmitrii A. Trunin
We establish the correspondence between the classical and quantum butterfly effects in nonlinear vector mechanics with the broken symmetry. On one hand, we analytically calc…
Large topological quantum computer
Nikita Kolganov, Sergey Mironov, Andrey Morozov
Chern-Simons topological quantum computer is a device that can be effectively described by the Chern-Simons topological quantum field theory and used for quantum computations. Quan…
Generalized unimodular gravity as a form of k-essence
A. O. Barvinsky, N. Kolganov, A. Vikman
We consider modifications of general relativity characterized by a special noncovariant constraint on metric coefficients, which effectively generates a perfect-fluid type of matte…
Quantum -matrices as universal qubit gates
Nikita Kolganov, Andrey Morozov
We study the Chern-Simons approach to the topological quantum computing. We use quantum -matrices as universal quantum gates and study the approximations of some one-q…
Inflation in generalized unimodular gravity
A. O. Barvinsky, N. Kolganov
The recently suggested generalized unimodular gravity theory, which was originally put forward as a model of dark energy, can serve as a model of cosmological inflation driven by t…
Dynamics of the generalized unimodular gravity theory
A. O. Barvinsky, N. Kolganov, A. Kurov +1
The Hamiltonian formalism of the generalized unimodular gravity theory, which was recently suggested as a model of dark energy, is shown to be a complicated example of constrained…