5,544 research outputs found
Topological Polaritons in a Quantum Spin Hall Cavity
We study the topological structure of matter-light excitations, so called
polaritons, in a quantum spin Hall insulator coupled to photonic cavity modes.
We identify a topological invariant in the presence of time reversal (TR)
symmetry, and demonstrate the existence of a TR-invariant topological phase. We
find protected helical edge states with energies below the lower polariton
branch and characteristic uncoupled excitonic states, both detectable by
optical techniques. Applying a Zeeman field allows us to relate the topological
index to the double coverage of the Bloch sphere by the polaritonic pseudospin.Comment: 5 pages + 4 pages supplemental material, 3 figure
Dynamical Locking of the Chiral and the Deconfinement Phase Transition in QCD
We study the fixed-point structure of four-fermion interactions in two-flavor
QCD with Nc colors close to the finite-temperature phase boundary. In
particular, we analyze how the fixed-point structure of four-fermion
interactions is related to the confining dynamics in the gauge sector. We show
that there exists indeed a mechanism which dynamically locks the chiral phase
transition to the deconfinement phase transition. This mechanism allows us to
determine a window for the values of physical observables in which the two
phase transitions lie close to each other.Comment: 14 pages, 5 figure
Computation and visualization of photonic quasicrystal spectra via Blochs theorem
Previous methods for determining photonic quasicrystal (PQC) spectra have
relied on the use of large supercells to compute the eigenfrequencies and/or
local density of states (LDOS). In this manuscript, we present a method by
which the energy spectrum and the eigenstates of a PQC can be obtained by
solving Maxwells equations in higher dimensions for any PQC defined by the
standard cut-and-project construction, to which a generalization of Blochs
theorem applies. In addition, we demonstrate how one can compute band
structures with defect states in the higher-dimensional superspace with no
additional computational cost. As a proof of concept, these general ideas are
demonstrated for the simple case of one-dimensional quasicrystals, which can
also be solved by simple transfer-matrix techniques.Comment: Published in Physical Review B, 77 104201, 200
Cavity Polariton Condensate in a Disordered Environment
We report on the influence of disorder on an exciton-polariton condensate in
a ZnO based bulk planar microcavity and compare experimental results with a
theoretical model for a non-equilibrium condensate. Experimentally, we detect
intensity fluctuations within the far-field emission pattern even at high
condensate densities which indicates a significant impact of disorder. We show
that these effects rely on the driven dissipative nature of the condensate and
argue that they can be accounted for by spatial phase inhomogeneities induced
by disorder, which occur even for increasing condensate densities realized in
the regime of high excitation power. Thus, non-equilibrium effects strongly
suppress the stabilization of the condensate against disorder, contrarily to
what is expected for equilibrium condensates in the high density limit.
Numerical simulations based on our theoretical model reproduce the experimental
data.Comment: main article and supplementary, 13 pages, 8 figures (main article
Machine detector interface for the future circular collider
The international Future Circular Collider (FCC) study aims at a design of
, , colliders to be built in a new 100 km tunnel in the Geneva
region. The collider (FCC-ee) has a centre of mass energy range
between 90 (Z-pole) and 375 GeV (tt_bar). To reach such unprecedented energies
and luminosities, the design of the interaction region is crucial. The
crab-waist collision scheme has been chosen for the design and it will be
compatible with all beam energies. In this paper we will describe the machine
detector interface layout including the solenoid compensation scheme. We will
describe how this layout fulfills all the requirements set by the parameters
table and by the physical constraints. We will summarize the studies of the
impact of the synchrotron radiation, the analysis of trapped modes and of the
backgrounds induced by single beam and luminosity effects giving an estimate of
the losses in the interaction region and in the detector.Comment: 6 pages, 7 figures, 62th ICFA ABDW on High Luminosity Circular
Colliders, eeFACT2018, Hong Kong, Chin
Search for Neutral Higgs Bosons of the Minimal Supersymmetric Standard Model in e+e- Interactions at root(s)=192-202GeV
A search for the lightest neutral CP-even and the neutral CP-odd Higgs bosons
of the Minimal Supersymmetric Standard Model is performed using 233.2 pb-1 of
integrated luminosity collected with the L3 detector at LEP at centre-of-mass
energies 192-202 GeV. No signal is observed and lower mass limits are given as
a function of tan(beta) for two scalar top mixing hypotheses. For tan(beta)
greater than 0.8, they are mh > 83.4 GeV and mA > 83.8 GeV at 95 % confidence
level
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
- âŚ