Spin-orbit interaction entangles the orbitals with the different spins. The spin-orbital-entangled states were discovered in surface states of topological insulators. However, the spin-orbital-entanglement is not specialized in the topological surface states. Here, we show the spin-orbital texture in a surface state of Bi(111) by laser-based spin- and angle-resolved photoelectron spectroscopy (...

We introduce the nonlinear spin-coherent state (SCS) via its ladder operator formalism and propose a type of nonlinear SCS by the nonlinear time evolution of the SCS. By a new version of spectroscopic squeezing criteria we study the spin squeezing in both the SCS and the nonlinear SCS. The results show that the SCS is not squeezed in the x, y and z directions, and the nonlinear SCS may be squee...

The disclosure of the magnetic and spinon superconductivities in hole-doped Bi 2 Sr 2 CaCu 2 O 8+x (Bi2212) cuprate raises the question about the origin of the superconductivity in other cuprates and specially in an electron-doped Nd 2-x Ce x CuO 4 (NCCO) cuprate. The superconductivity (SC) in copper-oxide materials or the high-T c superconductivity (HTSC) is an extraordinary phenomenon. The cu...

We demonstrate control over the spin state of a semiconductor quantum dot exciton using a polarized picosecond laser pulse slightly detuned from a biexciton resonance. The control pulse follows an earlier pulse, which generates an exciton and initializes its spin state as a coherent superposition of its two nondegenerate eigenstates. The control pulse preferentially couples one component of the...

We develop the formulation of the spin(SU(2)) coherent state path integrals based on arbitrary fiducial vectors. The resultant action in the path integral expression extensively depends on the vector; It differs from the conventional one in that it has a generalized form having some additional terms. We also study, as physical applications, the geometric phases associated with the coherent stat...

We relate the quantum dynamics of the Bose-Hubbard model (BHM) to the semiclassical nonlinear equations that describe an array of interacting Bose condensates by implementing a standard variational procedure based on the coherent state method. We investigate the dynamics of the two-site BHM from the purely quantum viewpoint by recasting first the model within a spin picture and using then the r...

We show that the ground state of an attractive Bose gas in a double well evolves from a coherent state to a Schrödinger Cat like state as the tunneling barrier is decreased. The latter exhibits super-fragmentation similar to the ground state of a spin-1 Bose gas with antiferromagnetic interactions. We also show that the fragmented condensates of attractive and repulsive Bose gases in double wel...

An electron within a mesoscopic (quantum-coherent) spintronic structure is described by a single wave function which, in the presence of both charge scattering and spin-orbit coupling, encodes an information about entanglement of its spin and orbital degrees of freedom. The quantum state—an improper mixture—of experimentally detectable spin subsystem is elucidated by evaluating quantum informat...