344 research outputs found
Out-of-equilibrium states and quasi-many-body localization in polar lattice gases
The absence of energy dissipation leads to an intriguing out-of-equilibrium
dynamics for ultracold polar gases in optical lattices, characterized by the
formation of dynamically-bound on-site and inter-site clusters of two or more
particles, and by an effective blockade repulsion. These effects combined with
the controlled preparation of initial states available in cold gases
experiments can be employed to create interesting out-of-equilibrium states.
These include quasi-equilibrated effectively repulsive 1D gases for attractive
dipolar interactions and dynamically-bound crystals. Furthermore,
non-equilibrium polar lattice gases can offer a promising scenario for the
study of many-body localization in the absence of quenched disorder. This
fascinating out-of-equilibrium dynamics for ultra-cold polar gases in optical
lattices may be accessible in on-going experiments.Comment: 5+1 pages, 4+1 figure
Phase separation and pairing regimes in the one-dimensional asymmetric Hubbard model
We address some open questions regarding the phase diagram of the
one-dimensional Hubbard model with asymmetric hopping coefficients and balanced
species. In the attractive regime we present a numerical study of the passage
from on-site pairing dominant correlations at small asymmetries to
charge-density waves in the region with markedly different hopping
coefficients. In the repulsive regime we exploit two analytical treatments in
the strong- and weak-coupling regimes in order to locate the onset of phase
separation at small and large asymmetries respectively.Comment: 13 pages, RevTeX 4, 12 eps figures, some additional refs. with
respect to v1 and citation errors fixe
The glazed tiles from the Qutb Shahi Tombs complex (Hyderabad, India): morphological and compositional characterization
Dipolar-induced resonance for ultracold bosons in a quasi-one-dimensional optical lattice
We study the role of the dipolar-induced resonance (DIR) in a quasi-one-dimensional system of ultracold bosons. We first describe the effect of the DIR on two particles in a harmonic trap. Then, we consider a deep optical lattice loaded with ultracold dipolar bosons. In order to describe this system, we introduce a novel atom-dimer extended Bose-Hubbard model, which is the minimal model correctly accounting for the DIR. We analyze the impact of the DIR on the phase diagram at T=0 by exact diagonalization of a small-sized system. We show that the DIR strongly affects this phase diagram. In particular, we predict the mass density wave to occur in a narrow domain corresponding to weak nearest-neighbor interactions, and we predict the occurrence of a collapse phase for stronger dipolar interactions. © 2013 American Physical Society
Dipolar-Induced Resonance for Ultracold Bosons in a Quasi-1D Optical Lattice
We study the role of the Dipolar-Induced Resonance (DIR) in a
quasi-one-dimensional system of ultracold bosons. We first describe the effect
of the DIR on two particles in a harmonic trap. Then, we consider a deep
optical lattice loaded with ultracold dipolar bosons. In order to describe this
system, we introduce a novel atom-dimer extended Bose-Hubbard model, which is
the minimal model correctly accounting for the DIR. We analyze the impact of
the DIR on the phase diagram at T=0 by exact diagonalization of a small-sized
system. We show that the DIR strongly affects this phase diagram. In
particular, we predict the mass density wave to occur in a narrow domain
corresponding to weak nearest-neighbor interactions, and the occurrence of a
collapse phase for stronger dipolar interactions.Comment: 6 pages, 10 figure
Coupling ultracold matter to dynamical gauge fields in optical lattices: From flux attachment to ℤ2 lattice gauge theories
From the standard model of particle physics to strongly correlated electrons, various physical settings are formulated in terms of matter coupled to gauge fields. Quantum simulations based on ultracold atoms in optical lattices provide a promising avenue to study these complex systems and unravel the underlying many-body physics. Here, we demonstrate how quantized dynamical gauge fields can be created in mixtures of ultracold atoms in optical lattices, using a combination of coherent lattice modulation with strong interactions. Specifically, we propose implementation of ℤ2 lattice gauge theories coupled to matter, reminiscent of theories previously introduced in high-temperature superconductivity. We discuss a range of settings from zero-dimensional toy models to ladders featuring transitions in the gauge sector to extended two-dimensional systems. Mastering lattice gauge theories in optical lattices constitutes a new route toward the realization of strongly correlated systems, with properties dictated by an interplay of dynamical matter and gauge fields
Cyclin B1-Cdk1 facilitates MAD1 release from the nuclear pore to ensure a robust spindle checkpoint.
How the cell rapidly and completely reorganizes its architecture when it divides is a problem that has fascinated researchers for almost 150 yr. We now know that the core regulatory machinery is highly conserved in eukaryotes, but how these multiple protein kinases, protein phosphatases, and ubiquitin ligases are coordinated in space and time to remodel the cell in a matter of minutes remains a major question. Cyclin B1-Cdk is the primary kinase that drives mitotic remodeling; here we show that it is targeted to the nuclear pore complex (NPC) by binding an acidic face of the kinetochore checkpoint protein, MAD1, where it coordinates NPC disassembly with kinetochore assembly. Localized cyclin B1-Cdk1 is needed for the proper release of MAD1 from the embrace of TPR at the nuclear pore so that it can be recruited to kinetochores before nuclear envelope breakdown to maintain genomic stability
CP Violation Results from B Decays at BaBar
In the present paper we review recent experimental results from the BaBar
experiment concerning the measurement of the CKM angles. A particular highlight
is given to the novel independent determination of the angle alpha from B0 ->
a_1(1260)+/- pi -/+ and to the recent full-luminosity updates of several angle
gamma measurements.Comment: 8 pages, contributed to the Proceedings of DISCRETE2010 Conferenc
Percutaneous Trans-Thoracic Procedures in Children With Tumors of Thoracic Wall, Mediastinum and Lung. The Experience of a Single Institution
Background
While percutaneous trans-thoracic procedures (PTTP) are commonly performed in adults with
tumors of thoracic wall, mediastinum and lung, the experience is limited in children, in whom
however less invasive methods should be the choice for the diagnosis or the identification of
small pulmonary nodules that need to be removed, sparing lung tissue. The results of the PTTP
performed by the interventional radiologists in our Pediatric Surgery Department are analyzed.
Methods
CT-guided biopsies, utilizing a 64-slice CTscanner, with low-radiation dose, were performed
applying the coaxial technique with 16-18G needles with a single tissue path. For localization
of lung nodules before surgery, two 20G-hook wires were positioned beyond the nodule. CT
images after each manipulation of the needles were obtained. US-guided biopsies were
performed either with or without coaxial technique through a needle bracket. Younger patients
required sedation. All patients underwent a chest radiogram two hours after the procedure and
remained under observation for 24 hours.
Results
From January 2015 to March 2019, 23 procedures were performed in 22 patients (Age:16M-
19Y): 6 patients underwent CT-guided biopsy (4 lung nodules, 2 mediastinal mass); 3
underwent 4 CT-guided hook-wire localization of pulmonary nodules, just before surgery; 13
underwent US-guided biopsy (posterior mediastinum 2; anterior mediastinum 5,
thoracic/intrathoracic mass 5). Adequate core biopsies were obtained in all patients, except
three, who underwent thoracoscopy/thoracotomy. The hook-wires were successfully
positioned in all cases, as confirmed by histology. After the procedure, two patients presented
perilesional hemorrhage and one pneumothorax, but they did not required treatment.
Conclusion
PTTP were successful in most patients, without significant complications. These techniques
should be encouraged to avoid diagnostic aggressive surgical approaches in children with
cancer. For all cases a multidisciplinary team is essential to discuss the indications and planning
the procedures
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