arXiv subjects

V. Gritsev

Publications and source records attributed to V. Gritsev.

26 records · Page 2Linked to original sources

arXiv2007

Preparation and detection of magnetic quantum phases in optical superlattices

We describe a novel approach to prepare, detect and characterize magnetic quantum phases in ultra-cold spinor atoms loaded in optical superlattices. Our technique makes use of singlet-triplet spin manipulations in an array of isolated double well potentials in analogy to recently demonstrated quantum control in semiconductor quantum dots. We also discuss the many-body singlet-triplet spin dynamics arising from coherent coupling between nearest neighbor double wells and derive an effective description for such system. We use it to study the generation of complex magnetic states by adiabatic and non-equilibrium dynamics.

cond-mat.other↗

arXiv2006

Tunneling conductance of a mesoscopic ring with spin-orbit coupling and Tomonaga-Luttinger interaction

We study the tunneling current through a mesoscopic two-terminal ring with spin-orbit coupling, which is threaded by a magnetic flux. The electron-electron interaction in the ring is described in terms of a Tomonaga-Luttinger model which also allows us to account for a capacitive coupling between the ring and the gate electrode. In the regime of weak tunneling, we describe how, at temperatures lower than the mean level spacing, the peak positions of the conductance depend on magnetic flux, spin-orbit coupling strength, gate voltage, charging energy, and interaction parameters (charge and spin velocity and stiffness).

cond-mat.mes-hall↗

arXiv2006

Screening properties of the two-dimensional electron gas with spin-orbit coupling

We study screening properties of the two-dimensional electron gas with Rashba spin-orbit coupling. Calculating the dielectric function within the random phase approximation, we describe the new features of screening induced by spin-orbit coupling, which are the extension of the region of particle-hole excitations and the spin-orbit-induced suppression of collective modes. The required polarization operator is calculated in an analytic form without any approximations. Carefully deriving its static limit, we prove the absence of a small-$q$ anomaly at zero frequency. On the basis of our results at finite frequencies we establish the new boundaries of the particle-hole continuum and calculate the SO-induced lifetime of collective modes such as plasmons and longitudinal optical phonons. According to our estimates, these effects can be resolved in inelastic Raman scattering. We evaluate the experimentally measurable dynamic structure factor and establish the range of parameters where the described phenomena are mostly pronounced.

cond-mat.mes-hall↗

arXiv2005

Screening in the two-dimensional electron gas with spin-orbit coupling

We study the interplay between electron-electron interaction and Rashba spin-orbit coupling in the two-dimensional electron gas. Using the random phase approximation we predict new screening properties of the electron gas which result in extension of the region of particle-hole excitations and in spin-orbit induced suppression of collective modes. In particular, we observe that the spin-orbit coupling gives a finite lifetime to plasmons and longitudinal optical phonons, which can be resolved in inelastic Raman scattering. We evaluate the experimentally measurable dynamic structure factor and estimate the range of parameters where the described phenomena are mostly pronounced.

cond-mat.mes-hall↗

arXiv2005

Competing effects of interactions and spin-orbit coupling in a quantum wire

We study the interplay of electron-electron interactions and Rashba spin-orbit coupling in one-dimensional ballistic wires. Using the renormalization group approach we construct the phase diagram in terms of Rashba coupling, Tomonaga-Luttinger stiffness and backward scattering strength. We identify the parameter regimes with a dynamically generated spin gap and show where the Luttinger liquid prevails. We also discuss the consequences for the operation of the Datta-Das transistor.

cond-mat.mes-hall↗

arXiv2004

Persistent currents in multicomponent Tomonaga-Luttinger liquid: application to mesoscopic semiconductor ring with spin-orbit interaction

We study persistent currents in semiconductor ballistic rings with spin-orbit Rashba interaction. We use as a working model the multicomponent Tomonaga-Luttinger liquid which arises due to the nonparabolic dispersion relations of electrons in the rings with rather strong spin-orbit coupling. This approach predicts some new characteristic features of persistent currents, which may be observed in experimental studies of semiconductor ballistic rings.

cond-mat.mes-hall↗

arXiv2004

Phase Diagram of the Heisenberg Spin Ladder with Ring Exchange

We investigate the phase diagram of a generalized spin-1/2 quantum antiferromagnet on a ladder with rung, leg, diagonal, and ring-exchange interactions. We consider the exactly soluble models associated with the problem, obtain the exact ground states which exist for certain parameter regimes, and apply a variety of perturbative techniques in the regime of strong ring-exchange coupling. By combining these approaches with considerations related to the discrete Z_4 symmetry of the model, we present the complete phase diagram.

cond-mat.str-el↗

arXiv2003

Exactly soluble isotropic spin-1/2 ladder models

The undeformed limit of the dilute two-color braid-monoid algebra gives a natural basis for the description of spin-1/2 ladder models, and allows different Baxterization Ansatze. Based on this observation we find an entire class of exactly soluble generalized isotropic spin-1/2 lader models.

cond-mat.str-el↗