22,877 research outputs found
Stability of the U(1) spin liquid with spinon Fermi surface in 2+1 dimensions
We study the stability of the 2+1 dimensional U(1) spin liquid state against
proliferation of instantons in the presence of spinon Fermi surface. By mapping
the spinon Fermi surface into an infinite set of 1+1 dimensional chiral
fermions, it is argued that an instanton has an infinite scaling dimension for
any nonzero number of spinon flavors. Therefore, the spin liquid phase is
stable against instantons and the non-compact U(1) gauge theory is a good low
energy description.Comment: 14 pages, 7 figures, v3) minor corrections, to appear in PR
Low-temperature ion beam mixing of Pt and Si markers in Ge
The mixing of Pt and Si marker atoms in Ge during 750-keV Xe irradiation was measured at temperatures between 6 and 500 K. The low-temperature measurements show that the mixing parameter for Pt is nearly twice that for Si. This result is in strong contradiction to the collisional theory of ion beam mixing. A weak temperature dependence in the mixing is found for both markers
Suppression of Phase Decoherence in a Single Atomic Qubit
We study the suppression of noise-induced phase decoherence in a single
atomic qubit by employing pulse sequences. The atomic qubit is composed of a
single neutral atom in a far-detuned optical dipole trap and the phase
decoherence may originate from the laser intensity and beam pointing
fluctuations as well as magnetic field fluctuations. We show that suitable
pulse sequences may prolongate the qubit coherence time substantially as
comparing to the conventional spin echo pulse.Comment: 4 pages, 3 figure
Fractionalized topological insulators from frustrated spin models in three dimensions
We present a theory of three dimensional fractionalized topological
insulators in the form of U(1) spin liquids with gapped fermionic spinons in
the bulk and topologically protected gapless spinon surface states. Starting
from a spin-1/2 model on a pyrochlore lattice, with frustrated
antiferromagnetic and ferromagnetic exchange interactions, we show that
decomposition of the latter interactions, within slave-fermion representation
of the spins, can naturally give rise to an emergent spin-orbit coupling for
the spinons. This stabilizes a fractionalized topological insulators which also
have bulk bond spin-nematic order. Finally, we describe the low energy
properties of these states.Comment: 10 page
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