arXiv subjects

Anatoliy I. Lotkov

Publications and source records attributed to Anatoliy I. Lotkov.

3 recordsLinked to original sources

arXiv2026

From coupled $\mathbb{Z}_3$ Rabi models to the $\mathbb{Z}_3$ Potts model

We study $\mathbb{Z}_3$-symmetric Rabi model that describes a three-level system coupled to two bosonic modes. We derive a mapping of the two-mode $\mathbb{Z}_3$ Rabi model onto a qubit-boson ring. This mapping allows us to formulate a realistic implementation of the $\mathbb{Z}_3$ Rabi model based on superconducting qubits. It also provides context for the previously proposed optomechanical implementation of the $\mathbb{Z}_3$ Rabi model. In addition, we propose a physical implementation of the $\mathbb{Z}_3$ Potts model via a coupled chain of $\mathbb{Z}_3$ Rabi models.

quant-ph↗

arXiv2025

Cat states in one- and two-mode $\mathbb{Z}_3$ Rabi models

We investigate one- and two-mode variants of the $\mathbb{Z}_3$-symmetric quantum Rabi model, which describe the interaction of a qutrit with one or two bosonic modes and are directly relevant for circuit-QED and spin-qudit platforms. We find a canonical transformation that allows one to obtain the spectrum of the $\mathbb{Z}_3$ Rabi model using perturbation theory in a magnetic field. We show that in a certain parameter regime (deep-strong-coupling and a small magnetic field) the three lowest eigenstates become $\mathbb{Z}_3$ qutrit-boson cat states. In order to characterize these states we introduce a joint qutrit-boson Wigner function and derive its closed-form expression for the qutrit-boson cat states. Numerical calculations across a wide range of coupling strengths show that the proposed Wigner function is a useful tool that allows one to unambiguously identify the $\mathbb{Z}_{3}$ qutrit-boson cat states.

quant-ph↗

arXiv2024

Quantum computation with hybrid parafermion-spin qubits

We propose a universal set of single- and two-qubit quantum gates acting on a hybrid qubit formed by coupling a quantum dot spin qubit to a $\mathbb{Z}_{2m}$ parafermion qubit with arbitrary integer $m$. The special case $m=1$ reproduces the results previously derived for Majorana qubits. Our formalism utilizes Fock parafermions, facilitating a transparent treatment of hybrid parafermion-spin systems. Furthermore, we highlight the previously overlooked importance of particle-hole symmetry in these systems. We give concrete examples how the hybrid qubit system could be realized experimentally for $\mathbb{Z}_4$ and $\mathbb{Z}_6$ parafermions. In addition, we discuss a simple readout scheme for the fractional parafermion charge via the measurement of the spin qubit resonant frequency.

cond-mat.mes-hall↗