240 research outputs found
Engineering Holographic Superconductor Phase Diagrams
We study how to engineer holographic models with features of a high
temperature superconductor phase diagram. We introduce a field in the bulk
which provides a tunable "doping" parameter in the boundary theory. By
designing how this field changes the effective masses of other order parameter
fields, desired phase diagrams can be engineered. We give examples of
generating phase diagrams with phase boundaries similar to a superconducting
dome and an anti-ferromagnetic phase by including two order parameter fields.
We also explore whether the pseudo gap phase can be described without adding
another order parameter field and discuss the potential scaling symmetry
associated with a quantum critical point hidden under the superconducting dome
in this phase diagram.Comment: 25 pages, 7 figure
Towards Searching for Entangled Photons in the CMB Sky
We explore the possibility of detecting entangled photon pairs from cosmic
microwave background or other cosmological sources coming from two patches of
the sky. The measurements use two detectors with different photon polarizer
directions. When two photon sources are separated by a large angle relative to
the earth, such that each detector has only one photon source in its field of
view, a null test of unentangled photons can be performed. The deviation from
this unentangled background is, in principle, the signature of photon
entanglement. To confirm whether the deviation is consistent with entangled
photons, we derive a photon polarization correlation to compare with, similar
to that in a Bell inequality measurement. However, since photon coincidence
measurement cannot be used to discriminate unentangled cosmic photons, it is
unlikely that the correlation expectation value alone can violate Bell
inequality to provide the signature for entanglement.Comment: 5 pages, 2 figure; references added, typos fixed. v3 revised version
with more discussions on detection possibilities; added references.v4
published version in PR
Uniqueness and structure of solutions to the Dirichlet problem for an elliptic system
AbstractIn this paper, we consider the Dirichlet problem for an elliptic system on a ball in R2. By investigating the properties for the corresponding linearized equations of solutions, and adopting the Pohozaev identity and Implicit Function Theorem, we show the uniqueness and the structure of solutions
Interaction effects of pseudospin-based magnetic monopoles and kinks in a doped dipolar superlattice gas
Magnetic monopoles and kinks are topological excitations extensively
investigated in quantum spin systems, but usually they are studied in different
setups. We explore the conditions for the coexistence and the interaction
effects of these quasiparticles in the pseudospin chain of the atomic dipolar
superlattice gas. In this chain, the magnetic kink is the intrinsic
quasiparticle, and the particle/hole defect takes over the role of the
north/south magnetic monopole, exerting monopolar magnetic fields to
neighboring spins. A confinement effect between the monopole and kink is
revealed, which renormalizes the dispersion of the kink. The corresponding
dynamical deconfinement process is observed and arises due to the kink-antikink
annihilation. The rich interaction effects of the two quasiparticles could
stimulate corresponding investigations in bulk spin systems
Magnetic monopole induced polarons in atomic superlattices
Magnetic monopoles have been realized as emergent quasiparticles in both
condensed matter and ultracold atomic platforms, with growing interests in the
coupling effects between the monopole and different magnetic quasiparticles. In
this work, interaction effects between monopoles and magnons are investigated
for an atomic pseudospin chain. We reveal that the monopole can excite a
virtual magnon cloud in the paramagnetic chain, thereby giving rise to a new
type of polaron, the monopole-cored polaron (McP). The McP is composed of the
monopole as the impurity core and the virtual magnon excitation as the dressing
cloud. The magnon dressing facilitates the Dirac string excitation and impacts
the monopole hopping. This induces an anti-trapping effect of the McP, which
refers to the fact that the dressing enhances the mobility of the McP, in
contrast to the self-trapping of the common polarons. Moreover, heterogeneous
bipolarons are shown to exist under the simultaneous doping of a north and a
south monopole. The heterogeneous bipolaron possesses an inner degree of
freedom composed of two identical impurities. Our investigation sheds light on
the understanding of how the coupling between the impurity core and the
dressing cloud can engineer the property of the polaro
Manifold formation and crossings of ultracold lattice spinor atoms in the intermediate interaction regime
Ultracold spinor atoms in the weak and strong interaction regime have
received extensive investigations, while the behavior in the intermediate
regime is less understood. We numerically investigate ultracold spinor atomic
ensembles of finite size in the intermediate interaction regime, and reveal the
evolution of the eigenstates from the strong to the intermediate regime. In the
strong interaction regime, it has been well known that the low-lying
eigenenergy spectrum presents the well-gaped multi-manifold structure, and the
energy gaps protect the categorization of the eigenstates. In the intermediate
interaction regime, it is found that the categorization of the eigenstates is
preserved, and the eigenenergy spectrum become quasi-continuum, with different
manifolds becoming overlapped. The overlapping induces both direct and avoided
crossings between close-lying manifolds, which is determined by the combined
symmetries of the eigenstates involved in the crossing. A modified t-J model is
derived to describe the low-lying eigenstates in the intermediate regime, which
can capture the formation and crossings of the manifolds. State preparation
through the avoided crossings is also investigated.Comment: 8 pages,6 figure
Critical Roles of STAT3 in β-Adrenergic Functions in the Heart
BACKGROUND:
β-Adrenergic receptors (βARs) play paradoxical roles in the heart. On one hand, βARs augment cardiac performance to fulfill the physiological demands, but on the other hand, prolonged activations of βARs exert deleterious effects that result in heart failure. The signal transducer and activator of transcription 3 (STAT3) plays a dynamic role in integrating multiple cytokine signaling pathways in a number of tissues. Altered activation of STAT3 has been observed in failing hearts in both human patients and animal models. Our objective is to determine the potential regulatory roles of STAT3 in cardiac βAR-mediated signaling and function.
METHODS AND RESULTS:
We observed that STAT3 can be directly activated in cardiomyocytes by β-adrenergic agonists. To follow up this finding, we analyzed βAR function in cardiomyocyte-restricted STAT3 knockouts and discovered that the conditional loss of STAT3 in cardiomyocytes markedly reduced the cardiac contractile response to acute βAR stimulation, and caused disengagement of calcium coupling and muscle contraction. Under chronic β-adrenergic stimulation, Stat3cKO hearts exhibited pronounced cardiomyocyte hypertrophy, cell death, and subsequent cardiac fibrosis. Biochemical and genetic data supported that Gαs and Src kinases are required for βAR-mediated activation of STAT3. Finally, we demonstrated that STAT3 transcriptionally regulates several key components of βAR pathway, including β1AR, protein kinase A, and T-type Ca(2+) channels.
CONCLUSIONS:
Our data demonstrate for the first time that STAT3 has a fundamental role in βAR signaling and functions in the heart. STAT3 serves as a critical transcriptional regulator for βAR-mediated cardiac stress adaption, pathological remodeling, and heart failure
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