121280181
Anyons emerging from fermions with conventional two-body interactions
Emergent anyons are the key elements of the topological quantum computation and topological quantum memory. We study a two-component fermion model with conventional two-body interaction in a fine-tuned external field and show that several subsets in the low-lying excitations obey the same fusion rules as those of the toric code model. Those string-like (or domain wall) excitations whose energy congregates in a small spatial region (a wall) may be thought of as quasiparticles which, in a given subset, obey mutual semionic statistics. We show how to peel off one of such subsets from other degenerate subsets and manipulate anyons in cold dipolar Fermi atoms or cold dipolar fermionic heteronuclear molecules in optical lattices by means of the established techniques.
67823811
Isotropic Landau levels of Dirac fermions in high dimensions
We generalize the Landau levels of two-dimensional Dirac fermions to three dimensions and above with the full rotational symmetry. Similarly to the two-dimensional case, there exists a branch of zero energy Landau levels of fractional fermion modes for the massless Dirac fermions. The spectra of other Landau levels distribute symmetrically with respect to the zero energy scaling with the square root of the Landau-level indices. This mechanism is a nonminimal coupling of Dirac fermions to the background fields. This high dimensional relativistic Landau-level problem is a square-root problem of its previous studied nonrelativistic version investigated in Li and Wu [arXiv:1103.5422 (2011)].
119230046
Captures of hot and warm sterile antineutrino dark matter on EC-decaying 63Ho nuclei
Capturing low-energy electron antineutrinos on radioactive 163Ho nuclei, which decay into 163Dy via electron capture (EC), is a noteworthy opportunity to detect relic sterile antineutrinos. Such hypothetical particles are more or less implied by current experimental and cosmological data, and they might be a part of hot dark matter or a candidate for warm dark matter in the Universe. Using the isotope 163Ho as a target and assuming reasonable active-sterile antineutrino mixing angles, we calculate the capture rate of relic electron antineutrinos against the corresponding EC-decay background in the presence of sterile antineutrinos at the sub-eV or keV mass scale. We show that the signature of hot or warm sterile antineutrino dark matter should in principle be observable, provided the target is big enough and the energy resolution is good enough.
18559665
Topological sigma-models with H-flux and twisted generalized complex manifolds
We study the topological sector of N = 2 sigma-models with HH-flux. It has been known for a long time that the target-space geometry of these theories is not Kahler and can be described in terms of a pair of complex structures, which do not commute, in general, and are parallel with respect to two different connections with torsion. Recently an alternative description of this geometry was found, which involves a pair of commuting twisted generalized complex structures on the target space. In this paper, we define and study the analogs of A and B-models for N = 2 sigma-models with HH-flux and show that the results are naturally expressed in the language of twisted generalized complex geometry. For example, the space of topological observables is given by the cohomology of a Lie algebroid associated to one of the two twisted generalized complex structures. We determine the topological scalar product, which endows the algebra of observables with the structure of a Frobenius algebra. We also discuss mirror symmetry for twisted generalized Calabi-Yau manifolds.
119187687
CP-violating Phases in Active-Sterile Solar Neutrino Oscillations
The effects of CP-violating phases in active-sterile solar neutrino oscillations are discussed in a general scheme of 3 + N-s mixing, without any constraint on the mixing between the three active and the Ns sterile neutrinos, assuming only a realistic hierarchy of neutrino mass-squared differences. A generalized Parke formula describing the neutrino oscillation probabilities inside the Sun is calculated. The validity of the analytical calculation and the probability variation due to the unknown CP-violating phases are illustrated with a numerical calculation of the evolution equation in the case of 3 + 1 neutrino mixing.
122282326
Direct detection of hot dark matter including light sterile neutrinos
Both active and sterile sub-eV neutrinos can serve for hot dark matter (DM) in the Universe. We consider the beta-decaying (e.g., 3H) and EC-decaying (e.g., 163Ho) nuclei as the most promising targets to capture hot DM in the laboratory. We calculate the capture rates of relic electron neutrinos and antineutrinos against the corresponding beta decay or electron capture (EC) decay backgrounds in different flavor mixing schemes. We stress that such direct measurements of hot DM might not be hopeless in the long term.
124761141
Population transfer to supercritical bound states during pair creation
We study the electron-positron pair-creation process from the vacuum under a very strong electric field. The external field is so strong that discrete states can dive into the negative energy continuum (the Dirac sea). This process is simultaneously associated with the onset of pair creation as well as the possibility for capturing the created electrons. By varying the total spatial width of the potential well, we can shift these trapping states in and out of the negative energy continuum while keeping the associated electric force the same. We compute the population transfer in and out of these states by solving the corresponding quantum field theoretical equations for the field operator on a space-time grid. We compare the population of these states obtained by projecting the time-evolved states on instantaneous energy eigenstates with the kinetic-energy spectrum of the ejected positrons.