2,280 research outputs found
Two proposals for testing quantum contextuality of continuous-variable states
We investigate the violation of non-contextuality by a class of continuous
variable states, including variations of entangled coherent states (ECS's) and
a two-mode continuous superposition of coherent states. We generalise the
Kochen-Specker (KS) inequality discussed in A. Cabello, Phys. Rev. Lett. {\bf
101}, 210401 (2008) by using effective bidimensional observables implemented
through physical operations acting on continuous variable states, in a way
similar to an approach to the falsification of Bell-CHSH inequalities put
forward recently. We test for state-independent violation of KS inequalities
under variable degrees of state entanglement and mixedness. We then demonstrate
theoretically the violation of a KS inequality for any two-mode state by using
pseudo-spin observables and a generalized quasi-probability function.Comment: 7 pages, 2 figures, RevTeX
Control of a two-dimensional electron gas on SrTiO3(111) by atomic oxygen
We report on the formation of a two-dimensional electron gas (2DEG) at the
bare surface of (111) oriented SrTiO3. Angle resolved photoemission experiments
reveal highly itinerant carriers with a 6-fold symmetric Fermi surface and
strongly anisotropic effective masses. The electronic structure of the 2DEG is
in good agreement with self-consistent tight-binding supercell calculations
that incorporate a confinement potential due to surface band bending. We
further demonstrate that alternate exposure of the surface to ultraviolet light
and atomic oxygen allows tuning of the carrier density and the complete
suppression of the 2DEG.Comment: 5 pages, 4 figure
Neutron Calibration Sources in the Daya Bay Experiment
We describe the design and construction of the low rate neutron calibration
sources used in the Daya Bay Reactor Anti-neutrino Experiment. Such sources are
free of correlated gamma-neutron emission, which is essential in minimizing
induced background in the anti-neutrino detector. The design characteristics
have been validated in the Daya Bay anti-neutrino detector.Comment: 13 pages, 7 figure
Quasiparticle dynamics and spin-orbital texture of the SrTiO3 two-dimensional electron gas
Two-dimensional electron gases (2DEGs) in SrTiO have become model systems
for engineering emergent behaviour in complex transition metal oxides.
Understanding the collective interactions that enable this, however, has thus
far proved elusive. Here we demonstrate that angle-resolved photoemission can
directly image the quasiparticle dynamics of the -electron subband ladder of
this complex-oxide 2DEG. Combined with realistic tight-binding supercell
calculations, we uncover how quantum confinement and inversion symmetry
breaking collectively tune the delicate interplay of charge, spin, orbital, and
lattice degrees of freedom in this system. We reveal how they lead to
pronounced orbital ordering, mediate an orbitally-enhanced Rashba splitting
with complex subband-dependent spin-orbital textures and markedly change the
character of electron-phonon coupling, co-operatively shaping the low-energy
electronic structure of the 2DEG. Our results allow for a unified understanding
of spectroscopic and transport measurements across different classes of
SrTiO-based 2DEGs, and yield new microscopic insights on their functional
properties.Comment: 10 pages including supplementary information, 4+4 figure
Neutrino oscillations from the splitting of Fermi points
As was shown previously, oscillations of massless neutrinos may be due to the
splitting of multiply degenerate Fermi points. In this Letter, we give the
details and propose a three-flavor model of Fermi point splittings and neutrino
mixings with only two free parameters. The model may explain recent
experimental results from the K2K and KamLAND collaborations. There is also
rough agreement with the data on atmospheric neutrinos (SuperK) and solar
neutrinos (SNO), but further analysis is required. Most importantly, the Ansatz
allows for relatively strong T-violating (CP-nonconserving) effects in the
neutrino sector.Comment: 6 pages with jetplFRK.cls, v4: published versio
New Measurement of Antineutrino Oscillation with the Full Detector Configuration at Daya Bay
We report a new measurement of electron antineutrino disappearance using the fully constructed Daya Bay Reactor Neutrino Experiment. The final two of eight antineutrino detectors were installed in the summer of 2012. Including the 404 days of data collected from October 2012 to November 2013 resulted in a total exposure of 6.9 x 10(5) GW(th) ton days, a 3.6 times increase over our previous results. Improvements in energy calibration limited variations between detectors to 0.2%. Removal of six Am-241-C-13 radioactive calibration sources reduced the background by a factor of 2 for the detectors in the experimental hall furthest from the reactors. Direct prediction of the antineutrino signal in the far detectors based on the measurements in the near detectors explicitly minimized the dependence of the measurement on models of reactor antineutrino emission. The uncertainties in our estimates of sin(2)2 theta(13) and vertical bar Delta m(ee)(2)vertical bar were halved as a result of these improvements. An analysis of the relative antineutrino rates and energy spectra between detectors gave sin(2)2 theta(13) = 0.084 +/- 0.005 and vertical bar Delta m(ee)(2)vertical bar = (2.42 +/- 0.11) x 10(-3) eV(2) in the three-neutrino framework
Assessment of aspirin resistance varies on a temporal basis in patients with ischaemic heart disease
The relationship between circulating concentrations of C-reactive protein, inflammatory cytokines and cytokine receptors in patients with non-small-cell lung cancer
Collapse of the Mott gap and emergence of a nodal liquid in lightly doped SrIrO
Superconductivity in underdoped cuprates emerges from an unusual electronic
state characterised by nodal quasiparticles and an antinodal pseudogap. The
relation between this state and superconductivity is intensely studied but
remains controversial. The discrimination between competing theoretical models
is hindered by a lack of electronic structure data from related doped Mott
insulators. Here we report the doping evolution of the Heisenberg
antiferromagnet SrIrO, a close analogue to underdoped cuprates. We
demonstrate that metallicity emerges from a rapid collapse of the Mott gap with
doping, resulting in lens-like Fermi contours rather than disconnected Fermi
arcs as observed in cuprates. Intriguingly though, the emerging electron liquid
shows nodal quasiparticles with an antinodal pseudogap and thus bares strong
similarities with underdoped cuprates. We conclude that anisotropic pseudogaps
are a generic property of two-dimensional doped Mott insulators rather than a
unique hallmark of cuprate high-temperature superconductivity
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