804 research outputs found
New methods in conformal partial wave analysis
We report on progress concerning the partial wave analysis of higher
correlation functions in conformal quantum field theory.Comment: 16 page
Jacobi Identity for Vertex Algebras in Higher Dimensions
Vertex algebras in higher dimensions provide an algebraic framework for
investigating axiomatic quantum field theory with global conformal invariance.
We develop further the theory of such vertex algebras by introducing formal
calculus techniques and investigating the notion of polylocal fields. We derive
a Jacobi identity which together with the vacuum axiom can be taken as an
equivalent definition of vertex algebra.Comment: 35 pages, references adde
Elliptic Thermal Correlation Functions and Modular Forms in a Globally Conformal Invariant QFT
Global conformal invariance (GCI) of quantum field theory (QFT) in two and
higher space-time dimensions implies the Huygens' principle, and hence,
rationality of correlation functions of observable fields (see Commun. Math.
Phys. 218 (2001) 417-436; hep-th/0009004). The conformal Hamiltonian has
discrete spectrum assumed here to be finitely degenerate. We then prove that
thermal expectation values of field products on compactified Minkowski space
can be represented as finite linear combinations of basic (doubly periodic)
elliptic functions in the conformal time variables (of periods 1 and )
whose coefficients are, in general, formal power series in
involving spherical functions of the "space-like"
fields' arguments. As a corollary, if the resulting expansions converge to
meromorphic functions, then the finite temperature correlation functions are
elliptic. Thermal 2-point functions of free fields are computed and shown to
display these features. We also study modular transformation properties of
Gibbs energy mean values with respect to the (complex) inverse temperature
(). The results are used to obtain the
thermodynamic limit of thermal energy densities and correlation functions.Comment: LaTex. 56 pages. The concept of global conformal invariance set in a
historical perspective (new Sect. 1.1 in the Introduction), references added;
minor corrections in the rest of the pape
Entire curves avoiding given sets in C^n
Let be a proper closed subset of and
at most countable (). We give conditions
of and , under which there exists a holomorphic immersion (or a proper
holomorphic embedding) with .Comment: 10 page
Randomized Benchmarking using Non-Destructive Readout in a 2D Atom Array
Neutral atoms are a promising platform for scalable quantum computing,
however prior demonstration of high fidelity gates or low-loss readout methods
have employed restricted numbers of qubits. Using randomized benchmarking of
microwave-driven single-qubit gates, we demonstrate single qubit gate errors of
on 225 atoms using conventional, destructive readout. This
exceeds the threshold for fault-tolerance. We further demonstrate suppression
of measurement errors via low-loss, non-destructive and state-selective readout
on 49 atoms. This enables post-selection for atom loss, which is a primary
source of errors in present setups.Comment: 6 pages, 4 figures plus Supplementary Materia
HATS-3b: An inflated hot Jupiter transiting an F-type star
We report the discovery by the HATSouth survey of HATS-3b, a transiting
extrasolar planet orbiting a V=12.4 F-dwarf star. HATS-3b has a period of P =
3.5479d, mass of Mp = 1.07MJ, and radius of Rp = 1.38RJ. Given the radius of
the planet, the brightness of the host star, and the stellar rotational
velocity (vsini = 9.0km/s), this system will make an interesting target for
future observations to measure the Rossiter-McLaughlin effect and determine its
spin-orbit alignment. We detail the low/medium-resolution reconnaissance
spectroscopy that we are now using to deal with large numbers of transiting
planet candidates produced by the HATSouth survey. We show that this important
step in discovering planets produces logg and Teff parameters at a precision
suitable for efficient candidate vetting, as well as efficiently identifying
stellar mass eclipsing binaries with radial velocity semi-amplitudes as low as
1 km/s.Comment: 11 pages, 10 figures, submitted to A
HATS-5b: A Transiting hot-Saturn from the HATSouth Survey
We report the discovery of HATS-5b, a transiting hot-Saturn orbiting a G type
star, by the HAT-South survey. HATS-5b has a mass of Mp=0.24 Mj, radius of
Rp=0.91 Rj, and transits its host star with a period of P=4.7634d. The radius
of HATS-5b is consistent with both theoretical and empirical models. The host
star has a V band magnitude of 12.6, mass of 0.94 Msun, and radius of 0.87
Rsun. The relatively high scale height of HATS-5b, and the bright,
photometrically quiet host star, make this planet a favourable target for
future transmission spectroscopy follow-up observations. We reexamine the
correlations in radius, equilibrium temperature, and metallicity of the
close-in gas-giants, and find hot Jupiter-mass planets to exhibit the strongest
dependence between radius and equilibrium temperature. We find no significant
dependence in radius and metallicity for the close-in gas-giant population.Comment: 10 pages, submitted to A
Radial velocity eclipse mapping of exoplanets
Planetary rotation rates and obliquities provide information regarding the
history of planet formation, but have not yet been measured for evolved
extrasolar planets. Here we investigate the theoretical and observational
perspective of the Rossiter-McLauglin effect during secondary eclipse (RMse)
ingress and egress for transiting exoplanets. Near secondary eclipse, when the
planet passes behind the parent star, the star sequentially obscures light from
the approaching and receding parts of the rotating planetary surface. The
temporal block of light emerging from the approaching (blue-shifted) or
receding (red-shifted) parts of the planet causes a temporal distortion in the
planet's spectral line profiles resulting in an anomaly in the planet's radial
velocity curve. We demonstrate that the shape and the ratio of the
ingress-to-egress radial velocity amplitudes depends on the planetary
rotational rate, axial tilt and impact factor (i.e. sky-projected planet
spin-orbital alignment). In addition, line asymmetries originating from
different layers in the atmosphere of the planet could provide information
regarding zonal atmospheric winds and constraints on the hot spot shape for
giant irradiated exoplanets. The effect is expected to be most-pronounced at
near-infrared wavelengths, where the planet-to-star contrasts are large. We
create synthetic near-infrared, high-dispersion spectroscopic data and
demonstrate how the sky-projected spin axis orientation and equatorial velocity
of the planet can be estimated. We conclude that the RMse effect could be a
powerful method to measure exoplanet spins.Comment: 7 pages, 3 figures, 1 table, accepted for publication in ApJ on 2015
June 1
The magnetic properties of Hf and Hf in the strong coupling deformed model
This paper reports NMR measurements of the magnetic dipole moments of two
high-K isomers, the 37/2, 51.4 m, 2740 keV state in Hf and the
8, 5.5 h, 1142 keV state in Hf by the method of on-line nuclear
orientation. Also included are results on the angular distributions of gamma
transitions in the decay of the Hf isotope. These yield high
precision E2/M1 multipole mixing ratios for transitions in bands built on the
23/2, 1.1 s, isomer at 1315 keV and on the 9/2, 0.663 ns, isomer at 321
keV. The new results are discussed in the light of the recently reported
finding of systematic dependence of the behavior of the g parameter
upon the quasi-proton and quasi-neutron make up of high-K isomeric states in
this region.Comment: 9 pages, 9 figures, accepted for publication in Physical Review
Into the UV: A Precise Transmission Spectrum of HAT-P-41b Using Hubble’s WFC3/UVIS G280 Grism
The ultraviolet–visible wavelength range holds critical spectral diagnostics for the chemistry and physics at work in planetary atmospheres. To date, time-series studies of exoplanets to characterize their atmospheres have relied on several combinations of modes on the Hubble Space Telescope's STIS/COS instruments to access this wavelength regime. Here for the first time, we apply the Hubble WFC3/UVIS G280 grism mode to obtain exoplanet spectroscopy from 200 to 800 nm in a single observation. We test the G280 grism mode on the hot Jupiter HAT-P-41b over two consecutive transits to determine its viability for the characterization of exoplanet atmospheres. We obtain a broadband transit depth precision of 29–33 ppm and a precision of on average 200 ppm in 10 nm spectroscopic bins. Spectral information from the G280 grism can be extracted from both the positive and negative first-order spectra, resulting in a 60% increase in the measurable flux. Additionally, the first Hubble Space Telescope orbit can be fully utilized in the time-series analysis. We present detailed extraction and reduction methods for use by future investigations with this mode, testing multiple techniques. We find the results to be fully consistent with STIS measurements of HAT-P-41b from 310 to 800 nm, with the G280 results representing a more observationally efficient and precise spectrum. HAT-P-41b's transmission spectrum is best fit with a model with T eq = 2091 K, high metallicity, and significant scattering and cloud opacity. With these first-of-their-kind observations, we demonstrate that WFC3/UVIS G280 is a powerful new tool to obtain UV–optical spectra of exoplanet atmospheres, adding to the UV legacy of Hubble and complementing future observations with the James Webb Space Telescope
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