64 research outputs found
Quantum reflection from an oscillating surface
We describe an experimentally realistic situation of the quantum reflection
of helium atoms from an oscillating surface. The temporal modulation of the
potential induces clear sidebands in the reflection probability as a function
of momentum. Theses sidebands could be exploited to slow down atoms and
molecules in the experiment.Comment: 9 pages, 4 figure
S-Wave Superconductivity in Anisotropic Holographic Insulators
Within gauge/gravity duality, we consider finite density systems in a helical
lattice dual to asymptotically anti-de Sitter space-times with Bianchi VII
symmetry. These systems can become an anisotropic insulator in one direction
while retaining metallic behavior in others. To this model, we add a
charged scalar and show that below a critical temperature, it forms a spatially
homogeneous condensate that restores isotropy in a new superconducting ground
state. We determine the phase diagram in terms of the helix parameters and
perform a stability analysis on its IR fixed point corresponding to a finite
density condensed phase at zero temperature. Moreover, by analyzing
fluctuations about the gravity background, we study the optical conductivity.
Due to the lattice, this model provides an example for a holographic
insulator-superfluid transition in which there is no unrealistic delta-function
peak in the normal phase DC conductivity. Our results suggest that in the zero
temperature limit, all degrees of freedom present in the normal phase condense.
This, together with the breaking of translation invariance, has implications
for Homes' and Uemuras's relations. This is of relevance for applications to
real world condensed matter systems. We find a range of parameters in this
system where Homes' relation holds.Comment: 59 pages, 17 figures and 1 tabl
Bosonic Gaussian states from conformal field theory
We study nonchiral wave functions for systems with continuous spins obtained
from the conformal field theory (CFT) of a free, massless boson. In contrast to
the case of discrete spins, these can be treated as bosonic Gaussian states,
which allows us to efficiently compute correlations and entanglement properties
both in one (1D) and in two spatial dimensions (2D). In 1D, the computed
entanglement entropy and spectra are in agreement with the underlying CFT.
Furthermore, we construct a 1D parent Hamiltonian with a low-energy spectrum
corresponding to that of a free, massless boson. In 2D, we find edge
excitations in the entanglement spectrum, although the states do not have
intrinsic topological order, as revealed by a determination of the topological
entanglement entropy.Comment: 18 pages, 8 figures, v2: accepted versio
The bumpy road of purinergic inhibitors to clinical application in immune-mediated diseases
Purinergic signaling plays important roles throughout the body in the regulation of organ functions during and following the disruption of homeostasis. This is also reflected by the widespread expression of two families of purinergic receptors (P1 and P2) with numerous subtypes. In the last few decades, there has been increasing evidence that purinergic signaling plays an important role in the regulation of immune functions. Mainly, signals mediated by P2 receptors have been shown to contribute to immune system-mediated pathologies. Thus, interference with P2 receptors may be a promising strategy for the modulation of immune responses. Although only a few clinical studies have been conducted in isolated entities with limited success, preclinical work suggests that the use of P2 receptor inhibitors may bear some promise in various autoimmune diseases. Despite the association of P2 receptors with several disorders from this field, the use of P2 receptor antagonists in clinical therapy is still very scarce. In this narrative review, we briefly review the involvement of the purinergic system in immunological responses and clinical studies on the effect of purinergic inhibition on autoimmune processes. We then open the aperture a bit and show some preclinical studies demonstrating a potential effect of purinergic blockade on autoimmune events. Using suramin, a non-specific purinergic inhibitor, as an example, we further show that off-target effects could be responsible for observed effects in immunological settings, which may have interesting implications. Overall, we believe that it is worthwhile to further investigate this hitherto underexplored area
Field tensor network states
We define a class of tensor network states for spin systems where the individual tensors are functionals of fields. The construction is based on the path-integral representation of correlators of operators in quantum field theory. These tensor network states are infinite-dimensional versions of matrix product states and projected entangled pair states. We find the field tensor that generates the Haldane-Shastry wave function and extend it to two dimensions. We give evidence that the latter underlies the topological chiral state described by the Kalmeyer-Laughlin wave function
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