The lifetime of the entangled states of interacting qubits in external elds and the thermostat calculated by path integral approach

In this paper we study the quantum entanglement of two identical qubits which interact with external electromagnetic elds and the thermostat and each other by time-dependent dipole-dipole interaction. We develop original method in path integral approach for numerical calculation of density matrix and Peres-Horodecki parameter (the measure of qubits entanglement). The results indicate on possibility of high-entanglement states exiting and long-time non-destructive control of them

Nonperturbative Approach to the Description of Molecular Excitation by Ultrashort Laser Pulses

We study the problem of excitation of molecules by an ultrashort laser pulse sequence by the use of path-integral approach in energy states space. Using numerical calculations of path-integral we evaluate laser field parameters at which there are quantum resonances in rotational dynamics of dinitrogen isotopes. So we describe recent experimental results [Phys. Rev. Lett. 109, 043003 (2012)] theoretically

Nonperturbative Approach to the Description of Molecular Excitation by Ultrashort Laser Pulses

We study the problem of excitation of molecules by an ultrashort laser pulse sequence by the use of path-integral approach in energy states space. Using numerical calculations of path-integral we evaluate laser field parameters at which there are quantum resonances in rotational dynamics of dinitrogen isotopes. So we describe recent experimental results [Phys. Rev. Lett. 109, 043003 (2012)] theoretically

Sustainable Entangled State of Two Qutrits Under Laser Irradiation

We study the evolution of quantum entanglement in the model of two identical qubits interacting with a single-mode laser field. The density matrix and Peres-Horodecki parameter are calculated within the frameworks of path-integral formalism. The quantum entanglement measure is shown to be strongly dependent upon the phase difference between the laser radiation acting on each cubit. This observation may offer the possibility of quantum entanglement stationary control by varying the distance between the qubits

Sustainable Entangled State of Two Qutrits Under Laser Irradiation

We study the evolution of quantum entanglement in the model of two identical qubits interacting with a single-mode laser field. The density matrix and Peres-Horodecki parameter are calculated within the frameworks of path-integral formalism. The quantum entanglement measure is shown to be strongly dependent upon the phase difference between the laser radiation acting on each cubit. This observation may offer the possibility of quantum entanglement stationary control by varying the distance between the qubits

Entangled state lifetime of qubits in external fields calculation by path integral approach

В работе исследуется квантовая перепутанность двух идентичных кубитов, взаимодействующих с электромагнитным полем и друг с другом посредством диполь-дипольного взаимодействия, зависящего от времени. Представлен оригинальный метод численного вычисления статистической матрицы плотности и параметра Переса-Городецких (меры квантовой перепутанности) в рамках формализма интегрирования по траекториям. Используя полученные формулы, мы исследуем зависимость между мерой квантовой перепутанности и амплитудой и частотой величины диполь-дипольного взаимодействия, а также разностью фаз кубитов. Полученные результаты указывают на возможность возбуждения перепутанных состояний с высоким временем жизни. In this paper we study the quantum entanglement of two identical qubits which interact with electromagnetic field and each other by time-dependent dipole-dipole interaction. We develop original method in path integral approach for numerical calculation of density matrix and Peres-Horodecki parameter (the measure of qubits entanglement). By the use of obtained equations we investigate the dependence of quantum entanglement on dipole-dipole interaction amplitude and frequency as well as qubits phase difference. The results indicate on possibility of high-entanglement states exiting and long-time non-destructive control of them

Modeling of multiphoton ionization of atoms and molecules by the path integral method

Вероятность квантовых переходов молекулы между ее состояниями под действием электромагнитного поля представляется как интеграл по траекториям от действительного знакопеременного функционала. Предложен метод вычисления интеграла с использованием рекуррентных соотношений. Метод прилагается для описания процессов многофотонных атомов и молекул. The probability of quantum transitions of a molecule between its states under the action of an electromagnetic field is represented as an integral over trajectories from a real alternating functional. A method is proposed for computing the integral using recurrence relations. The method is applied to describe the processes of multiphoton atoms and molecules

Nonperturbative Approach to the Description of Molecular Excitation by Ultrashort Laser Pulses

We study the problem of excitation of molecules by an ultrashort laser pulse sequence by the use of path-integral approach in energy states space. Using numerical calculations of path-integral we evaluate laser field parameters at which there are quantum resonances in rotational dynamics of dinitrogen isotopes. So we describe recent experimental results [Phys. Rev. Lett. 109, 043003 (2012)] theoretically