199675868
Exotic topological density waves in cold atomic Rydberg fermions
118637791
Topological orbital ladders
Synthetic quantum orbital materials, such as the recent double-well optical lattices loaded with s and p orbital atoms [1, 2], open an avenue to exploit symmetries beyond natural crystals. Exotic superfluid states were reported for bosons. Here, we unveil a topological phase of interacting fermions on a two-leg ladder of unequal parity orbitals, derived from the experimentally realized double-well lattices by dimension reduction. Z2 topological invariant originates simply from the staggered phases of sp-orbital quantum tunneling, requiring none of the previously known mechanisms such as spin-orbit coupling or artificial gauge field. Another unique feature is that upon crossing over to two dimensions with coupled ladders, the edge modes from each ladder form a parity-protected flat band at zero energy, opening the route to strongly correlated states controlled by interactions. Experimental signatures are found in density correlations and phase transitions to trivial band and Mott insulators. The uneven double-well potential formed by laser light has been developed into a powerful tool for quantum gases by numerous groups [1–6]. For instance, controls of atoms on the sand p-orbitals of the checkerboard [1] and hexagonal [6] optical lattices have been demonstrated, and correlation between these orbitals tends to give exotic quantum states [6, 7]. Motivated by these developments, we consider a lattice of uneven double-wells where fermionic atoms are loaded up to the sand porbital levels of the shallow and deep wells respectively, as shown in Fig. 1. The spatial symmetry of the orbital wave function dictates the complex hopping amplitudes between nearby sites. Under certain circumstances, as for the uneven double wells, the orbital hopping pattern is sufficient for producing topologically nontrivial band structures [8]. We will first focus on a one-dimensional ladder system illustrated in Fig. 1b and 1c. This corresponds to the quasi-one dimensional limit of a standard double-well optical lattice, with the optical potential given by
118417209
Cyclotron dynamics of interacting bosons in artificial magnetic fields
We study theoretically quantum dynamics of interacting bosons in artificial magnetic fields as engineered in recent ultracold atomic experiments, where quantum cyclotron orbital motion has been observed. With exact numerical simulations and perturbative analyses, we find that interactions induce damping in the cyclotron motion. The damping time is found to be dependent on interaction and tunneling strengths monotonically, while its dependence on magnetic flux is non-monotonic. Sufficiently strong interactions would render bosons dynamically localized inhibiting the cyclotron motion. The damping predicted by us can be construed as an interaction-induced quantum decoherence of the cyclotron motion.
118410842
$p$-wave chiral superfluidity from an $s$-wave interacting atomic Fermi gas
X iv :1 40 2. 59 95 v1 [ co nd -m at .q ua nt -g as ] 24 F eb 2 01 4 p-wave chiral superfluidity from an s-wave interacting atomic Fermi gas Bo Liu , Xiaopeng Li , Biao Wu, and W. Vincent Liu Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA 2 Condensed Matter Theory Center, University of Maryland, Co llege Park, MD 20742, USA Joint Quantum Institute, University of Maryland, College P ark, MD 20742, USA International Center for Quantum Materials, Peking University, Beijing 100871, China Collaborative Innovation Center of Quantum Matter, Beijin g, China (Dated: February 26, 2014) Abstract Chiralp-wave superfluids are fascinating topological quantum stat e of matter that have been found in the liquid 3He-A phase and arguably in the electronic Sr 2RuO4 superconductor. They are shown fundamentally related to the fractional 5/2 quantum Hall state which supports fractional exotic excita tions. A common understanding is that such states require spin-triplet pai ring of fermions due top-wave interaction. Here we report by controlled theoretical approximation that a cent er-of-mass Wannier p-wave chiral superfluid state can arise from spin-singlet pairing for an s-wave interacting atomic Fermi gas in an optical lattice. De spite a conceptually different origin, it shows topological prop erties similar to the conventional chiral p-wave state. These include a non-zero Chern number and the appeara nc of chiral fermionic zero modes bounded to domain walls. Several signature quantities are calculat ed for the cold atom experimental condition.
2179030
Weyl superfluidity in a three-dimensional dipolar Fermi gas.
Weyl superconductivity or superfluidity, a fascinating topological state of matter, features novel phenomena such as emergent Weyl fermionic excitations and anomalies. Here we report that an anisotropic Weyl superfluid state can arise as a low temperature stable phase in a 3D dipolar Fermi gas. A crucial ingredient of our model is a direction-dependent two-body effective attraction generated by a rotating external field. Experimental signatures are predicted for cold gases in radio-frequency spectroscopy. The finite temperature phase diagram of this system is studied and the transition temperature of the Weyl superfluidity is found to be within the experimental scope for atomic dipolar Fermi gases.
35621082
Local unitary classification of arbitrary dimensional multipartite pure states.
We propose a practical entanglement classification scheme for general multipartite pure states in arbitrary dimensions under local unitary equivalence by exploiting the high order singular value decomposition technique and local symmetries of the states. By virtue of this scheme, the method of determining the local unitary equivalence of n-qubit states proposed by Kraus is extended to the case for arbitrary dimensional multipartite states.
12120130
Modified Newton's gravity in Finsler space as a possible alternative to dark matter hypothesis
A modified Newton's gravity is obtained as the weak field approximation of the Einstein's equation in Finsler space. It is found that a specified Finsler structure makes the modified Newton's gravity equivalent to the modified Newtonian dynamics (MOND). In the framework of Finsler geometry, the flat rotation curves of spiral galaxies can be deduced naturally without invoking dark matter.
118721470
On the SO(10) instanton
A class of instantons in a four-dimensional Euclidean SO(10) model of grand unification is discussed. These solutions in the classical limit have nonzero Lagrangian density at only one single point. These instantons can generate baryon-number violation processes with rates which could be observable in the not too distant future.
118968482
Massive overlap fermions on anisotropic lattices
We formulate the massive overlap fermions on anisotropic lattices. We find that the dispersion relation for the overlap fermion resembles the continuum form in the low-momentum region once the bare parameters are properly tuned. The quark self-energy and the quark field renormalization constants are calculated to one-loop in bare lattice perturbation theory. Using tadpole improved perturbation theory, we establish the relation between the well-tuned parameters and the quark mass once the bare coupling is given. We argue that massive domain wall quarks might be helpful in lattice QCD studies on heavy-light hadron spectroscopy.
120176772
Design of the local trigger board for the Daya Bay reactor neutrino experiment
We have designed a local trigger board for the Daya Bay reactor neutrino experiment, which is aimed to measure the neutrino mixing angle sin(2) 2 theta(13) with a precision down to 1% level. The local trigger board processes both the total number of coincident photomultiplier tube (PMT) hits and the PMT energy sum to make trigger decisions. With this design, a high trigger probability is achieved to meet the system requirement. The design of the local trigger board is presented. (C) 2011 Elsevier B.V. All rights reserved.