Role of conical intersection seam topography in the chemiexcitation of 1,2-dioxetanes

Chemiexcitation of 1,2-dioxetanes is initiated by the cleavage of the O–O bond, then the molecule enters a region where nonadiabatic transitions to excited states are feasible. Does the surface topography explain chemiexcitation yield differences?

Controls of a superconducting quantum parametron under a strong pump field

Pumped at approximately twice the natural frequency, a Josephson parametric oscillator called parametron or Kerr parametric oscillator shows self-oscillation. Quantum annealing and universal quantum computation using self-oscillating parametrons as qubits were proposed. However, controls of parametrons under the pump field are degraded by unwanted rapidly oscillating terms in the Hamiltonian, which we call non-resonant rapidly oscillating terms (NROTs) coming from the violation of the rotating wave approximation. Therefore, the pump field can be an intrinsic origin of the imperfection of controls of parametrons. Here, we theoretically study the influence of the NROTs on the accuracy of controls of a parametron: a cat-state creation and a single-qubit gate. It is shown that there is a trade-off relationship between the suppression of the nonadiabatic transitions and the validity of the rotating wave approximation in a conventional approach. We also show that the tailored time dependence of the detuning of the pump field can suppress both of the nonadiabatic transitions and the disturbance of the state of the parametron due to the NROTs.

Evaluation of Mixed Quantum-Classical Molecular Dynamics on cis‐Azobenzene Photoisomerization

The quantitative prediction on nonadiabatic transitions between different electronic state is important to understand ultrafast processes in photochemistry. A variety of mixed quantum-classical molecular dynamics methods such as surface hopping...

Динамические смещения атомов и атермическое скольжение дислокаций в кристаллах

A dislocation glide mechanism at low temperatures is proposed. The mechanism is based on taking into account the dynamic displacements of atoms — displacements caused by nonadiabatic transitions of atoms in a crystal with a dislocation under the action of an external force. Dynamic displacements initiate the instability of a direct dislocation of relatively low-amplitude displacements during atomic vibrations. The development of instability leads to the formation of a double kink and a dislocation shift by one interatomic distance.

К теории инициирующего действия непрерывного нагрева на структурные перестройки и температуру фазового перехода в кристаллах

A model and kinetic theory of structural changes in crystals upon continuous heating are proposed. Nonadiabatic transitions of atoms between different states of a system of nuclei and electrons are taken into account. Non-adiabatic transitions initiate structural rearrangements determined by a change in the short-range order upon the redistribution of electron density. It was shown that continuous heating stimulates structural changes in the crystal and lowers the temperature of a known phase transition.