The magnetic phase diagrams, and other physical characteristics, of the hole– doped La2−xSrxCuO4 and electron–doped Nd2−xCexCuO4 high–temperature superconductors are profoundly different. Given that it is envisaged that the simplest Hamiltonians describing these systems are the same, viz. the t − t − J model, this is surprising. Here we relate these physical differences to their ground states’ ...

As a continuation of our previous work, we derive the optimal flux phase which minimizes the ground state energy in the one-dimensional many particle systems, when the number of particles is odd in the absence of on-site interaction and external potential. Moreover, we study the relationship between the flux on the ring and the spin of the ground state through which we derive some information o...

Investigating various spin-1/2 systems in two dimensions (2d), by means of exact diagonalization (ED) on small samples of N spins, we have found, up to now, four kinds of antiferromagnetic phases at T=0. Two of them display long range order (LRO): Néel or Valence Bond Crystal (VBC) LRO. The others are two different Spin-Liquids. The Néel case may be qualified as semi-classical: it is a groundst...

We suggest a numerical integration procedure for solving the equations of motion of certain classical spin systems which preserves the underlying symplectic structure of the phase space. Such symplectic integrators have been successfully utilized for other Hamiltonian systems, e. g. for molecular dynamics or non-linear wave equations. Our procedure rests on a decomposition of the spin Hamiltoni...

We study exciton polaritons in a two-dimensional Lieb lattice of micropillars. The energy spectrum of the system features two flat bands formed from S and P_{x,y} photonic orbitals, into which we trigger bosonic condensation under high power excitation. The symmetry of the orbital wave functions combined with photonic spin-orbit coupling gives rise to emission patterns with pseudospin texture i...

In this paper we attempt to reconstruct one of the last projects of Volodya Geyler which remained unfinished. We study motion of a quantum particle in the plane to which a halfline lead is attached assuming that the particle has spin 1 2 and the plane component of the Hamiltonian contains a spin-orbit interaction of either Rashba or Dresselhaus type. We construct the class of admissible Hamilto...

Spin chains have been proposed as quantum wires in many quantum-information processing architectures. Coherent transmission of quantum information in spin chains over short distances is enabled by their internal dynamics, which drives the transport of single-spin excitations in perfectly polarized chains. Given the practical challenge of preparing the chain in a pure state, we propose to use a ...

We present a hybrid classical/quantum algorithm for efficiently solving the eigenvalue problem of many-particle Hamiltonians on quantum computers with limited resources by splitting workload between classical and processors. This reduces needed number qubits at expense an increased evaluations. demonstrate method Hubbard model show how conservation z-component total spin allows spin-up spin-dow...

The possibility of observing factorized ground states in dimerized spin systems is studied. A set of sufficient conditions is derived which allows one to establish whether or not it is possible to have factorization both in nearestneighbor and long-range Hamiltonians. These conditions can be derived by forcing factorization for each of the pairwise terms of the total Hamiltonian. Due to the pec...