Publications de Dmitri Ivanov | EPFL Graph Search

Staggered flux state for rectangular-lattice spin-1/2 Heisenberg antiferromagnets

Dmitri Ivanov, Bastien Dalla Piazza, Henrik Moodysson Rønnow, Noore Elahi Shaik

We investigate the spin-1/2 Heisenberg model on a rectangular lattice, using the Gutzwiller projected variational wave function known as the staggered flux state. Using Monte Carlo techniques, the variational parameters and instantaneous spin-spin correlat ...

AMER PHYSICAL SOC2020

Fractional excitations in the square-lattice quantum antiferromagnet

Dmitri Ivanov, Bastien Dalla Piazza, Martin Mourigal, Henrik Moodysson Rønnow, Goran Nilsen, Mechthild Enderle

Quantum magnets have occupied the fertile ground between many-body theory and low-temperature experiments on real materials since the early days of quantum mechanics. However, our understanding of even deceptively simple systems of interacting spin-1/2 par ...

Nature Publishing Group2015

Magnetic interference patterns in long disordered Josephson junctions

Benoît Crouzy, Dmitri Ivanov

We study a diffusive superconductor–normal-metal–superconductor (SNS) junction in an external magnetic field. In the limit of a long junction, we find that the form of the dependence of the Josephson current on the field and on the length of the junction d ...

Amer Physical Soc2013

Hybridization of wave functions in one-dimensional localization

Dmitri Ivanov

A quantum particle can be localized in a disordered potential, the effect known as Anderson localization. In such a system, correlations of wave functions at very close energies may be described, due to Mott, in terms of a hybridization of localized states ...

2012

Vison excitations in near-critical quantum dimer models

Dmitri Ivanov

We study vison excitations in a quantum dimer model interpolating between the Rokhsar-Kivelson models on the square and triangular lattices. In the square-lattice case, the model is known to be critical and characterized by U(1) topological quantum numbers ...

2011

Phase transitions in full counting statistics for periodic pumping

Dmitri Ivanov

We discuss the problem of full counting statistics for periodic pumping. The probability generating function is usually defined on a circle of the "physical" values of the counting parameter, with its periodicity corresponding to charge quantization. The e ...

2010

Correlations of the local density of states in quasi-one-dimensional wires

Dmitri Ivanov

We report a calculation of the correlation function of the local density of states in a disordered quasi-one-dimensional wire in the unitary symmetry class at a small energy difference. Using an expression from the supersymmetric sigma model, we obtain the ...

2009

Effective spin-flip scattering in diffusive superconducting proximity systems with magnetic disorder

Dmitri Ivanov

We revisit the problem of diffusive proximity systems involving superconductors and normal metals (or ferromagnets) with magnetic disorder. On the length scales much larger than its correlation length, the effect of sufficiently weak magnetic disorder may ...

2009

Factorization of quantum charge transport for noninteracting fermions

Dmitri Ivanov

We show that the statistics of the charge transfer of noninteracting fermions through a two-lead contact is generalized binomial at any temperature and for any form of the scattering matrix: an arbitrary charge-transfer process can be decomposed into indep ...

2009

Statistics of quantum transfer of noninteracting fermions in multiterminal junctions

Dmitri Ivanov

Similarly to the recently obtained result for two-terminal systems, we show that there are constraints on the full counting statistics for noninteracting fermions in multiterminal contacts. In contrast to the two-terminal result, however, there is no facto ...

2009

Dyson-Maleev representation of nonlinear sigma models

Dmitri Ivanov

For nonlinear sigma models in the unitary symmetry class, the nonlinear target space can be parameterized with cubic polynomials. This choice of coordinates has been known previously as the Dyson-Maleev parameterization for spin systems, and we show that i ...

2008

Allowed charge transfers between coherent conductors driven by a time-dependent scatterer

Dmitri Ivanov

We derive constraints on the statistics of the charge transfer between two conductors in the model of arbitrary time-dependent instant scattering of noninteracting fermions at zero temperature. The constraints are formulated in terms of analytic properties ...

2008

Single hole and vortex excitations in the doped Rokhsar-Kivelson quantum dimer model on the triangular lattice

Samuel Bieri, Hugo Ribeiro, Dmitri Ivanov

We consider the doped Rokhsar-Kivelson quantum dimer model on the triangular lattice with one mobile hole (monomer) at the Rokhsar-Kivelson point. The motion of the hole is described by two branches of excitations: the hole may either move with or without ...

2007

Josephson current in a superconductor-ferromagnet-superconductor junction with in-plane ferromagnetic domains

Benoît Crouzy, Dmitri Ivanov

We study a diffusive superconductor-ferromagnet-superconductor (SFS) junction with in-plane ferromagnetic domains. Close to the superconducting transition temperature, we describe the proximity effect in the junction with the linearized Usadel equations [P ...

2007

Crystallization of the resonating valence bond liquid as vortex condensation

Frédéric Mila, Dmitri Ivanov

We show that the liquid-to-crystal quantum phase transition in the Rokhsar-Kivelson dimer model on the two-dimensional triangular lattice occurs as a condensation of vortexlike excitations called "visons." This conclusion is drawn from numerical studies of ...

2007

Dimer phases in quantum antiferromagnets with orbital degeneracy

Dmitri Ivanov

We study and solve the ground-state problem of a microscopic model for a family of orbitally degenerate quantum magnets. The orbital degrees of freedom are assumed to have a directional character and are represented by static Potts-like variables. In the l ...

2007

Josephson current in a superconductor-ferromagnet junction with two non-collinear magnetic domains

Benoît Crouzy, Dmitri Ivanov

We study the Josephson effect in a superconductor--ferromagnet--superconductor (SFS) junction with ferromagnetic domains of non-collinear magnetization. As a model for our study we consider a diffusive junction with two ferromagnetic domains along the junc ...

2006

Dynamics of the quantum dimer model on the triangular lattice: Soft modes and local resonating valence-bond correlations

Frédéric Mila, Dmitri Ivanov

We report on an exhaustive investigation of the dynamical dimer-dimer correlations in imaginary time for the quantum dimer model on the triangular lattice using the Green’s function Monte Carlo method. We show in particular that soft modes develop upon red ...

2006

Zero-temperature properties of the quantum dimer model on the triangular lattice

Frédéric Mila, Dmitri Ivanov

2005

Minigap in a SN junction with paramagnetic impurities

Benoît Crouzy, Dmitri Ivanov

We study the effect of spin-flip scattering on the density of states in a long diffusive S-N junction with transparent interface. We calculate the critical value of the spin-flip scattering rate at which the minigap closes and give the dependence of the mi ...

2005