It can be shown that the dynamics of the Landau-Zener model can be accurately described in terms of the Kibble-Zurek theory of the topological defect production in nonequilibrium phase transitions. The simplest quantum model exhibiting the Kibble-Zurek mechanism is presented. A new intuitive description of Landau-Zener dynamics is found.

We calculate the time evolution of Landau-Zener tunneling for atoms in an accelerating optical lattice. Analytical expressions are obtained that are in good agreement with a recent observation of nonexponential decay. We identify new experimental regimes that show a crossover from strong coherent oscillations to exponential decay in the temporal evolution of the survival probability. We establi...

We present a method to perform fault-tolerant single-qubit gate operations using Landau-Zener tunneling. In a single Landau-Zener pulse, the qubit transition frequency is varied in time so that it passes through the frequency of the radiation field. We show that a simple three-pulse sequence allows eliminating errors in the gate up to the third order in errors in the qubit energies or the radia...

It is theoretically known that the quantum interference of a long sequence of Landau-Zener transitions can result in Rabi oscillations. Because of its stringent requirements, however, this phenomenon has never been experimentally observed in the time domain. Using a nitrogen-vacancy (NV) center spin in isotopically purified diamond, we observed the Rabi oscillations resulting from more than 100...

We report a theoretical/experimental study of current-voltage characteristics I-V of graphene devices near the Dirac point. The I-V can be described by a power law I V with 1 1.5 . The exponent is higher when the mobility is lower. This superlinear I-V is interpreted in terms of the interplay between Zener-Klein transport, that is tunneling between different energy bands, and defect scattering....

The Landauer-Büttiker formalism combined with the tight-binding transfer matrix method is used to describe the results of recent experiments: the high tunneling magnetoresistance (TMR) in (Ga,Mn)As-based trilayers and highly polarized spin injection in p-(Ga,Mn)As/n-GaAs Zener diode. For both TMR and Zener spin current polarization, the calculated values agree well with those observed experimen...

Measurements of the Zener relaxation in single crystals of Cu-18at.%Au and Cu3Au are presented. In the laat.% alloy only one internal friction peak is observed at low frequencies (of the order of 1 Hz). This peak is only slightly wider than a Debye's peak. An additional hump appears at intermediate frequencies (of the order of 60 Hz). The Zener peak in the Cu3Au alloy is accompanied by an addit...

We study the influence of a fast noise on Landau-Zener transitions. We demonstrate that a fast colored noise much weaker than the conventional white noise can produce transitions itself or can change substantially the Landau-Zener transition probabilities. In the limit of fast colored or strong white noise we derive asymptotically exact formulas for transition probabilities and study the time e...

Non-adiabatic transitions are studied in a spin-boson model with multiple scattering points. In order to generalize the Landau–Zener formula, which describes the case of a single scattering point, we define an “effective gap” for a set of scattering points. The generalized formula agrees very well with numerical results of the nonadiabatic dynamics, which we obtained by a direct numerical metho...

Abstract We consider the level-crossing problem in a three-level system with non-linearly time-varying Hamiltonian (time-dependence t). We study the validity of the so-called independent crossing approximation in the Landau-Zener model by making comparison with results obtained numerically in density matrix approach. We also demonstrate the failure of the so-called ”nearest zero” approximation ...