The quantum spin liquid is an exotic quantum state of matter in magnets. This state is a spin analog of liquid helium that does not solidify down to the lowest temperature due to strong quantum fluctuations. In conventional fluids, the liquid and gas possess the same symmetry and adiabatically connect to each other by bypassing the critical end point. We find that the situation is qualitatively...

We model the spin polarized optoelectronic processes in a GaAs-based light emitting diode under injection of spin-filtered electrons. To describe the microscopic dynamics we derive the quantum Langevin equations for photon number and carrier numbers. The polarization degree of the light generated by light emitting diode is calculated and compared with the experiment results.

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...

We demonstrate a quantum coherent electron spin filter by directly measuring the spin polarization of emitted current. The spin filter consists of an open quantum dot in an in-plane magnetic field; the in-plane field gives the two spin directions different Fermi wavelengths resulting in spin-dependent quantum interference of transport through the device. The gate voltage is used to select the p...

We review recent theoretical developments about the role of spins, electron-electron interactions, and spin-orbit coupling in metal nanoparticles and semiconductor quantum dots. For a closed system, in the absence of spin-orbit coupling or of an external magnetic field, electron-electron interactions make it possible to have ground states with spin S > 1/2. We review here a theoretical analysis...

Submitted for the MAR06 Meeting of The American Physical Society GHz Optical Spin Transceiver1 PATRICK IRVIN, PETRU FODOR, JEREMY LEVY, University of Pittsburgh, COSMQC TEAM — The ability to measure spin coherence in semiconductor nanostructures is important for determining the feasibility of spin-based quantum computing architectures. Quantum dots are often referred to as ’solid-state atoms’ b...

We discuss the theory and experimental considerations of a quantum feedback scheme for producing deterministically reproducible spin squeezing. Continuous nondemolition atom number measurement from monitoring a probe field conditionally squeezes the sample. Simultaneous feedback of the measurement results controls the quantum state such that the squeezing becomes unconditional. We find that for...

Feasible external control of material properties is a crucial issue in condensed matter physics. A new approach to achieving this aim, named adiabatic photo-steering, is reviewed. The core principle of this scheme is that several material constants are effectively turned into externally tunable variables by irradiation of monochromatic laser light. Two-dimensional topological insulators are sel...

A topologically ordered material is characterized by a rare quantum organization of electrons that evades the conventional spontaneously broken symmetry-based classification of condensed matter. Exotic spin-transport phenomena, such as the dissipationless quantum spin Hall effect, have been speculated to originate from a topological order whose identification requires a spin-sensitive measureme...

We review recent theoretical developments about the role of spins, electron-electron interactions, and spin-orbit coupling in metal nanoparticles and semiconductor quantum dots. For a closed system, in the absence of spin-orbit coupling or of an external magnetic field, electron-electron interactions make it possible to have ground states with spin S > 1/2. We review here a theoretical analysis...