236 research outputs found
Reply to "Comment on `Inference with minimal Gibbs free energy in information field theory'" by Iatsenko, Stefanovska and McClintock
We endorse the comment on our recent paper [En{\ss}lin and Weig, Phys. Rev. E
82, 051112 (2010)] by Iatsenko, Stefanovska and McClintock [Phys. Rev. E 85
033101 (2012)] and we try to clarify the origin of the apparent controversy on
two issues. The aim of the minimal Gibbs free energy approach to provide a
signal estimate is not affected by their Comment. However, if one wants to
extend the method to also infer the a posteriori signal uncertainty any
tempering of the posterior has to be undone at the end of the calculations, as
they correctly point out. Furthermore, a distinction is made here between
maximum entropy, the maximum entropy principle, and the so-called maximum
entropy method in imaging, hopefully clarifying further the second issue of
their Comment paper.Comment: 1 page, no figures, Reply to Comment pape
Inference with minimal Gibbs free energy in information field theory
Non-linear and non-Gaussian signal inference problems are difficult to
tackle. Renormalization techniques permit us to construct good estimators for
the posterior signal mean within information field theory (IFT), but the
approximations and assumptions made are not very obvious. Here we introduce the
simple concept of minimal Gibbs free energy to IFT, and show that previous
renormalization results emerge naturally. They can be understood as being the
Gaussian approximation to the full posterior probability, which has maximal
cross information with it. We derive optimized estimators for three
applications, to illustrate the usage of the framework: (i) reconstruction of a
log-normal signal from Poissonian data with background counts and point spread
function, as it is needed for gamma ray astronomy and for cosmography using
photometric galaxy redshifts, (ii) inference of a Gaussian signal with unknown
spectrum and (iii) inference of a Poissonian log-normal signal with unknown
spectrum, the combination of (i) and (ii). Finally we explain how Gaussian
knowledge states constructed by the minimal Gibbs free energy principle at
different temperatures can be combined into a more accurate surrogate of the
non-Gaussian posterior.Comment: 14 page
Size-independent Young's modulus of inverted conical GaAs nanowire resonators
We explore mechanical properties of top down fabricated, singly clamped
inverted conical GaAs nanowires. Combining nanowire lengths of 2-9 m with
foot diameters of 36-935 nm yields fundamental flexural eigenmodes spanning two
orders of magnitude from 200 kHz to 42 MHz. We extract a size-independent value
of Young's modulus of (453) GPa. With foot diameters down to a few tens of
nanometers, the investigated nanowires are promising candidates for
ultra-flexible and ultra-sensitive nanomechanical devices
Scurvy presenting as vulvar folliculitis, a case report and review of the literature
This case examines clinical features and care of a patient with scurvy presenting with vulvar folliculitis
Optical detection of a BCS transition of Lithium-6 in harmonic traps
We study the detection of a BCS transition within a sample of Lithium--6
atoms confined in a harmonic trap. Using the local density approximation we
calculate the pair correlation function in the normal and superfluid state at
zero temperature. We show that the softening of the Fermi hole associated with
a BCS transition leads to an observable increase in the intensity of
off--resonant light scattered from the atomic cloud at small angles.Comment: 7 pages, 3 figures, submitted to Europhysics Letter
Gross karyotypic and phenotypic alterations among different progenies of the candida glabrata cbs138/atcc2001 reference strain
Peer reviewedPublisher PD
State tomography of capacitively shunted phase qubits with high fidelity
We introduce a new design concept for superconducting quantum bits (qubits)
in which we explicitly separate the capacitive element from the Josephson
tunnel junction for improved qubit performance. The number of two-level systems
(TLS) that couple to the qubit is thereby reduced by an order of magnitude and
the measurement fidelity improves to 90%. This improved design enables the
first demonstration of quantum state tomography with superconducting qubits
using single shot measurements.Comment: submitted to PR
Anisotropic optical conductivity of the putative Kondo insulator CeRuSn
Kondo insulators and in particular their non-cubic representatives have
remained poorly understood. Here we report on the development of an anisotropic
energy pseudogap in the tetragonal compound CeRuSn employing optical
reflectivity measurements in broad frequency and temperature ranges, and local
density approximation plus dynamical mean field theory calculations. The
calculations provide evidence for a Kondo insulator-like response within the
plane and a more metallic response along the c axis and qualitatively
reproduce the experimental observations, helping to identify their origin
Optomechanics for quantum technologies
The ability to control the motion of mechanical systems through interaction with light has opened the door to a plethora of applications in fundamental and applied physics. With experiments routinely reaching the quantum regime, the focus has now turned towards creating and exploiting interesting non-classical states of motion and entanglement in optomechanical systems. Quantumness has also shifted from being the very reason why experiments are constructed to becoming a resource for the investigation of fundamental physics and the creation of quantum technologies. Here, by focusing on opto- and electromechanical platforms we review recent progress in quantum state preparation and entanglement of mechanical systems, together with applications to signal processing and transduction, quantum sensing and topological physics, as well as small-scale thermodynamics
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