960 research outputs found
Atomic quantum gases in Kagom\'e lattices
We demonstrate the possibility of creating and controlling an ideal and
\textit{trimerized} optical Kagom\'e lattice, and study the low temperature
physics of various atomic gases in such lattices. In the trimerized Kagom\'e
lattice, a Bose gas exhibits a Mott transition with fractional filling factors,
whereas a spinless interacting Fermi gas at 2/3 filling behaves as a quantum
magnet on a triangular lattice. Finally, a Fermi-Fermi mixture at half filling
for both components represents a frustrated quantum antiferromagnet with a
resonating-valence-bond ground state and quantum spin liquid behavior dominated
by continuous spectrum of singlet and triplet excitations. We discuss the
method of preparing and observing such quantum spin liquid employing molecular
Bose condensates.Comment: 4 pages, 1 figure. Missing affiliations adde
Atomic Fermi gas in the trimerized Kagom\'e lattice at the filling 2/3
We study low temperature properties of an atomic spinless interacting Fermi
gas in the trimerized Kagom\'e lattice for the case of two fermions per trimer.
The system is described by a quantum spin 1/2 model on the triangular lattice
with couplings depending on bonds directions. Using exact diagonalizations we
show that the system exhibits non-standard properties of a {\it quantum
spin-liquid crystal}, combining a planar antiferromagnetic order with an
exceptionally large number of low energy excitations.Comment: 4 pages & 4 figures + 2 tables, better version of Fig.
Driving innovation for rare skin cancers: utilizing common tumours and machine learning to predict immune checkpoint inhibitor response
Metastatic Merkel cell carcinoma (MCC) and cutaneous squamous cell carcinoma (cSCC) are rare and both show impressive responses to immune checkpoint inhibitor treatment. However, at least 40% of patients do not respond to these expensive and potentially toxic drugs. Development of predictive biomarkers of response and rational, effective combination treatment strategies in these rare, often frail patient populations is challenging. This review discusses the pathophysiology and treatment of MCC and cSCC, with a particular focus on potential biomarkers of response to immunotherapy, and discusses how transfer learning using big data collected from patients with common tumours can be used in combination with deep phenotyping of rare tumours to develop predictive biomarkers and elucidate novel treatment targets
Atomic Bose-Fermi mixtures in an optical lattice
A mixture of ultracold bosons and fermions placed in an optical lattice
constitutes a novel kind of quantum gas, and leads to phenomena, which so far
have been discussed neither in atomic physics, nor in condensed matter physics.
We discuss the phase diagram at low temperatures, and in the limit of strong
atom-atom interactions, and predict the existence of quantum phases that
involve pairing of fermions with one or more bosons, or, respectively, bosonic
holes. The resulting composite fermions may form, depending on the system
parameters, a normal Fermi liquid, a density wave, a superfluid liquid, or an
insulator with fermionic domains. We discuss the feasibility for observing such
phases in current experiments.Comment: 4 pages, 1 eps figure, misprints correcte
Optimal directed searches for continuous gravitational waves
Wide parameter space searches for long lived continuous gravitational wave signals are computationally limited. It is therefore critically important that available computational resources are used rationally. In this paper we consider directed searches, i.e. targets for which the sky position is known accurately but the frequency and spindown parameters are completely unknown. Given a list of such potential astrophysical targets, we therefore need to prioritize. On which target(s) should we spend scarce computing resources? What parameter space region in frequency and spindown should we search? Finally, what is the optimal search set-up that we should use? In this paper we present a general framework that allows to solve all three of these problems. This framework is based on maximizing the probability of making a detection subject to a constraint on the maximum available computational cost. We illustrate the method for a simplified problem
- …