402 research outputs found
Supersolid phase with cold polar molecules on a triangular lattice
We study a system of heteronuclear molecules on a triangular lattice and
analyze the potential of this system for the experimental realization of a
supersolid phase. The ground state phase diagram contains superfluid, solid and
supersolid phases. At finite temperatures and strong interactions there is an
additional emulsion region, in contrast to similar models with short-range
interactions. We derive the maximal critical temperature and the
corresponding entropy for supersolidity and find feasible
experimental conditions for its realization.Comment: 4 pages, 4 figure
Quantum Phases of Cold Polar Molecules in 2D Optical Lattices
We discuss the quantum phases of hard-core bosons on a two-dimensional square
lattice interacting via repulsive dipole-dipole interactions, as realizable
with polar molecules trapped in optical lattices. In the limit of small
tunneling, we find evidence for a devil's staircase, where solid phases appear
at all rational fillings of the underlying lattice. For finite tunneling, we
establish the existence of extended regions of parameters where the groundstate
is a supersolid, obtained by doping the solids either with particles or
vacancies. Here the solid-superfluid quantum melting transition consists of two
consecutive second-order transitions, with a supersolid as the intermediate
phase. The effects of finite temperature and confining potentials relevant to
experiments are discussed.Comment: replaced with published versio
The Application of Hyaluronic Acid Injections in Functional and Aesthetic Andrology: A Narrative Review
Hyaluronic acid (HA) is a glycosaminoglycan widely utilised in different fields of medicine. We aimed to provide a comprehensive overview of the scientific evidence on the use of HA in andrology. A review of the literature to identify pertinent studies concerning the use of HA in andrology was carried out on the Medline, EMBASE, and the Cochrane databases, with no time restriction up to December 2022. Penile girth enlargement (PGE) using HA proved to be safe and effective in enhancing the diameter of the penis, with durable and satisfactory outcomes in long-term follow-up. Injection of HA in the glans seems to represent an alternative treatment option for those patients with premature ejaculation (PE) who fail to respond to conventional medications. HA intra-plaque injections represent a valid option which may contribute to restore sexual activity in patients with Peyronie's disease (PD). The adoption of HA filler injections should always be tailored to the patient's peculiar anatomy and underlying condition. More robust evidence is required to achieve a uniformed consensus regarding the use of HA in andrology, and further efforts should continue to improve the current injection techniques and HA products
Effect of Doublon-Holon Binding on Mott transition---Variational Monte Carlo Study of Two-Dimensional Bose Hubbard Models
To understand the mechanism of Mott transitions in case of no magnetic
influence, superfluid-insulator (Mott) transitions in the S=0 Bose Hubbard
model at unit filling are studied on the square and triangular lattices, using
a variational Monte Carlo method. In trial many-body wave functions, we
introduce various types of attractive correlation factors between a
doubly-occupied site (doublon, D) and an empty site (holon, H), which play a
central role for Mott transitions, in addition to the onsite repulsive
(Gutzwiller) factor. By optimizing distance-dependent parameters, we study
various properties of this type of wave functions. With a hint from the Mott
transition arising in a completely D-H bound state, we propose an improved
picture of Mott transitions, by introducing two characteristic length scales,
the D-H binding length and the minimum D-D exclusion length
. Generally, a Mott transition occurs when becomes
comparable to . In the conductive (superfluid) state, domains of
D-H pairs overlap with each other (); thereby D and
H can propagate independently as density carriers by successively exchanging
the partners. In contrast, intersite repulsive Jastrow (D-D and H-H) factors
have little importance for the Mott transition.Comment: 16 pages, 22 figures, submitted to J. Phys. Soc. Jp
Peyronie's disease development and management in diabetic men
Background: Peyronie's disease (PD) is a fibrosing disorder of the penis resulting in plaque formation and penile deformity that negatively affect sexual and psychosocial function of patients. A multifactorial etiology of PD is assumed with diabetes mellitus (DM) being a potential risk factor. Objectives: The aim of this narrative review was to investigate diabetes role in PD pathophysiology, diagnosis, and treatment. Materials and methods: A non-systematic narrative review of original articles, meta-analyses, and randomized trials was conducted, including articles in the pre-clinical setting to support relevant findings. Results: Diabetes is one of the most common comorbidity observed in PD patients, with a prevalence of about 11% and a strong association with erectile dysfunction (ED). DM is associated with both a higher risk of developing PD and has also an impact on the outcomes of PD's treatments. Discussion: Evidence from literature underlines that metabolic alterations typical of DM are pivotal factors in the development of PD and resistance to its medical treatment. Conclusion: The role of DM in development of PD is still debated, while its role in PD development is not completely clear, there is a clear impact of DM on PD treatment outcomes
Association between metabolic syndrome, obesity, diabetes mellitus and oncological outcomes of bladder cancer. A systematic review
Metabolic syndrome is a cluster of several metabolic abnormalities, its prevalence is increasing worldwide. To summarize the most recent evidence regarding the relationship between metabolic syndrome, its components and the oncological outcomes in bladder cancer patients, a National Center for Biotechnology Information PubMed search for relevant articles either published or e-published up to March 2014 was carried out by combining the following Patient population, Intervention, Comparison, Outcome terms: metabolic syndrome, obesity, body mass index, hyperglycemia, insulin resistance, diabetes, hypertension, dyslipidemia, bladder cancer, risk, mortality, cancer specific survival, disease recurrence and progression. Metabolic syndrome is a complex, highly prevalent disorder, and central obesity, insulin resistance, dyslipidemia and hypertension are its main components. Published findings would suggest that metabolic syndrome per se might be associated with an increased risk of bladder cancer in male patients, but it did not seem to confer a risk of worse prognosis. Considering the primary components of metabolic syndrome (hypertension, obesity and dyslipidemia), available data are uncertain, and it is no possible to reach a conclusion yet on either a direct or an indirect association with bladder cancer risk and prognosis. Only with regard to type 2 diabetes mellitus, available data would suggest a potential negative correlation. However, as the evaluation of bladder cancer risk and prognosis in patients with metabolic disorders is certainly complex, further studies are urgently required to better assess the actual role of these metabolic disorders
Ultracold Dipolar Gases in Optical Lattices
This tutorial is a theoretical work, in which we study the physics of
ultra-cold dipolar bosonic gases in optical lattices. Such gases consist of
bosonic atoms or molecules that interact via dipolar forces, and that are
cooled below the quantum degeneracy temperature, typically in the nK range.
When such a degenerate quantum gas is loaded into an optical lattice produced
by standing waves of laser light, new kinds of physical phenomena occur. These
systems realize then extended Hubbard-type models, and can be brought to a
strongly correlated regime. The physical properties of such gases, dominated by
the long-range, anisotropic dipole-dipole interactions, are discussed using the
mean-field approximations, and exact Quantum Monte Carlo techniques (the Worm
algorithm).Comment: 56 pages, 26 figure
Recreational Drug Misuse and Its Potential Contribution to Male Fertility Levelsâ Decline: A Narrative Review
Recreational drug intake may be associated with a range of medical untoward consequences, including male infertility. However, as the related evidence is still limited, the main outcome of this review is to provide a better understanding of the existence of any association between recreational drug misuse and male fertility levelsâ decline. Whilst searching the MEDLINE/PubMed, a comprehensive overview of the literature regarding male infertility and substances of abuse (e.g., phytocannabinoids, opiates/opioids, stimulants, âherbal highsâ, psychedelics, and ânovel psychoactive substances) was here undertaken. Due to the paucity of robust, high-quality, empirical, human studies, a narrative strategy was here preferred over a systematic approach. Relevant data are qualitatively analyzed and presented in a table. Although most available evidence is in support of a detrimental role of cannabis on human spermatogenesis, a few remaining studies failed to document any effect of this drug on seminal quality, and it is not clear to which extent this drug impacts fertility rates/time to pregnancy. The current understanding of the impact of opiate-, cocaine- and amphetamine/stimulant-misuse on human reproduction is widely unknown, and most studies dealing with this matter represent only an extrapolation of data derived from specific clinical circumstances. Although the message of âno smoking, no alcohol and no street drugsâ should always be offered as good health advice to all patients seeking medical help for fertility issues, robust scientific clinical evidence in support of a direct detrimental impact of recreational drugs on spermatogenesis is scant to date
Dipolar Bose-Einstein condensate soliton on a two-dimensional optical lattice
Using a three-dimensional mean-field model we study one-dimensional dipolar
Bose-Einstein condensate (BEC) solitons on a weak two-dimensional (2D) square
and triangular optical lattice (OL) potentials placed perpendicular to the
polarization direction. The stabilization against collapse and expansion of
these solitons for a fixed dipolar interaction and a fixed number of atoms is
possible for short-range atomic interaction lying between two critical limits.
The solitons collapse below the lower limit and escapes to infinity above the
upper limit. One can also stabilize identical tiny BEC solitons arranged on the
2D square OL sites forming a stable 2D array of interacting droplets when the
OL sites are filled with a filling factor of 1/2 or less. Such an array is
unstable when the filling factor is made more than 1/2 by occupying two
adjacent sites of OL. These stable 2D arrays of dipolar superfluid BEC solitons
are quite similar to the recently studied dipolar Mott insulator states on 2D
lattice in the Bose-Hubbard model by Capogrosso-Sansone et al. [B.
Capogrosso-Sansone, C. Trefzger, M. Lewenstein, P. Zoller, G. Pupillo, Phys.
Rev. Lett. 104 (2010) 125301].Comment: 8 pages, 5 figures and 2 table
Novel Mechanism of Supersolid of Ultracold Polar Molecules in Optical Lattices
We study the checkerboard supersolid of the hard-core Bose-Hubbard model with
the dipole-dipole interaction. This supersolid is different from all other
supersolids found in lattice models in the sense that superflow paths through
which interstitials or vacancies can hop freely are absent in the crystal. By
focusing on repulsive interactions between interstitials, we reveal that the
long-range tail of the dipole-dipole interaction have the role of increasing
the energy cost of domain wall formations. This effect produces the supersolid
by the second-order hopping process of defects. We also perform exact quantum
Monte Carlo simulations and observe a novel double peak structure in the
momentum distribution of bosons, which is a clear evidence for supersolid. This
can be measured by the time-of-flight experiment in optical lattice systems
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