1,312 research outputs found
Dirac Equation at Finite Temperature
In this paper, we propose finite temperature Dirac equation, which can
describe the quantum systems in an arbitrary temperature for a relativistic
particle of spin-1/2. When the temperature T=0, it become Dirac equation. With
the equation, we can study the relativistic quantum systems in an arbitrary
temperature.Comment: arXiv admin note: text overlap with arXiv:1005.2751,
arXiv:hep-ph/0004125, arXiv:hep-ph/0005272 by other author
A Mott insulator continuously connected to iron pnictide superconductors
Iron-based superconductivity develops near an antiferromagnetic order and out
of a bad metal normal state, which has been interpreted as originating from a
proximate Mott transition. Whether an actual Mott insulator can be realized in
the phase diagram of the iron pnictides remains an open question. Here we use
transport, transmission electron microscopy, X-ray absorption spectroscopy, and
neutron scattering to demonstrate that NaFeCuAs near
exhibits real space Fe and Cu ordering, and are antiferromagnetic insulators
with the insulating behavior persisting above the N\'eel temperature,
indicative of a Mott insulator. Upon decreasing from , the
antiferromagnetic ordered moment continuously decreases, yielding to
superconductivity around . Our discovery of a Mott insulating state in
NaFeCuAs thus makes it the only known Fe-based material in which
superconductivity can be smoothly connected to the Mott insulating state,
highlighting the important role of electron correlations in the high- superconductivity.Comment: in press, Nat. Commun., 4 figures, supplementary information
available upon reques
A Dynamic-Order Fractional Dynamic System
Multi-system interaction is an important and difficult problem in physics.
Motivated by the experimental result of an electronic circuit element
"Fractor", we introduce the concept of dynamic-order fractional dynamic system,
in which the differential-order of a fractional dynamic system is determined by
the output signal of another dynamic system. The new concept offers a
comprehensive explanation of physical mechanism of multi-system interaction.
The properties and potential applications of dynamic-order fractional dynamic
systems are further explored with the analysis of anomalous relaxation and
diffusion processes.Comment: 10 pages, 5 figure
The influence of direct -meson production to the determination on the nucleon strangeness asymmetry via dimuon events in neutrino experiments
Experimentally, the production of oppositely charged dimuon events by
neutrino and anti-neutrino deep inelastic scattering (DIS) is used to determine
the strangeness asymmetry inside a nucleon. Here we point out that the direct
production of -meson in DIS may make substantial influence to the
measurement of nucleon strange distributions. The direct -meson production
is via the heavy quark recombination (HQR) and via the light quark
fragmentation from perturbative QCD (LQF-P). To see the influence precisely, we
compute the direct -meson productions via HQR and LQF-P quantitatively and
estimate their corrections to the analysis of the strangeness asymmetry. The
results show that HQR has stronger effect than LQF-P does, and the former may
influence the experimental determination of the nucleon strangeness asymmetry.Comment: 9 latex pages, 7 figure
Experimental demonstration of a hyper-entangled ten-qubit Schr\"odinger cat state
Coherent manipulation of an increasing number of qubits for the generation of
entangled states has been an important goal and benchmark in the emerging field
of quantum information science. The multiparticle entangled states serve as
physical resources for measurement-based quantum computing and high-precision
quantum metrology. However, their experimental preparation has proved extremely
challenging. To date, entangled states up to six, eight atoms, or six photonic
qubits have been demonstrated. Here, by exploiting both the photons'
polarization and momentum degrees of freedom, we report the creation of
hyper-entangled six-, eight-, and ten-qubit Schr\"odinger cat states. We
characterize the cat states by evaluating their fidelities and detecting the
presence of genuine multi-partite entanglement. Small modifications of the
experimental setup will allow the generation of various graph states up to ten
qubits. Our method provides a shortcut to expand the effective Hilbert space,
opening up interesting applications such as quantum-enhanced super-resolving
phase measurement, graph-state generation for anyonic simulation and
topological error correction, and novel tests of nonlocality with
hyper-entanglement.Comment: 11 pages, 5 figures, comments welcom
ADH1B Arg47His Polymorphism Is Associated with Esophageal Cancer Risk in High-Incidence Asian Population: Evidence from a Meta-Analysis
with ESCC in Asian populations under a common ancestry scenario of the susceptibility loci, we combined all available studies into a meta-analysis.. Heterogeneity among studies and their publication bias were also tested. can bring more risk to ESCC (OR = 13.46, 95% CI: 2.32–78.07). allele
Bilateral transfer of motor performance as a function of motor imagery training: a systematic review and meta-analysis
ObjectiveThe objective of this review was to evaluate the efficacy of mental imagery training (MIT) in promoting bilateral transfer (BT) of motor performance for healthy subjects.Data sourcesWe searched 6 online-databases (Jul-Dec 2022) using terms: “mental practice,” “motor imagery training,” “motor imagery practice,” “mental training,” “movement imagery,” “cognitive training,” “bilateral transfer,” “interlimb transfer,” “cross education,” “motor learning,” “strength,” “force” and “motor performance.”Study selection and data extractionWe selected randomized-controlled studies that examined the effect of MIT on BT. Two reviewers independently determined if each study met the inclusion criteria for the review. Disagreements were resolved through discussion and, if necessary, by a third reviewer. A total of 9 articles out of 728 initially identified studies were chosen for the meta-analysis.Data synthesisThe meta-analysis included 14 studies for the comparison between MIT and no-exercise control (CTR) and 15 studies for the comparison between MIT and physical training (PT).ResultsMIT showed significant benefit in inducing BT compared to CTR (ES = 0.78, 95% CI = 0.57–0.98). The effect of MIT on BT was similar to that of PT (ES = –0.02, 95% CI = –0.15–0.17). Subgroup analyses showed that internal MIT (IMIT) was more effective (ES = 2.17, 95% CI = 1.57–2.76) than external MIT (EMIT) (ES = 0.95, 95% CI = 0.74–1.17), and mixed-task (ES = 1.68, 95% CI = 1.26–2.11) was more effective than mirror-task (ES = 0.46, 95% CI = 0.14–0.78) and normal-task (ES = 0.56, 95% CI = 0.23–0.90). No significant difference was found between transfer from dominant limb (DL) to non-dominant limb (NDL) (ES = 0.67, 95% CI = 0.37–0.97) and NDL to DL (ES = 0.87, 95% CI = 0.59–1.15).ConclusionThis review concludes that MIT can serve as a valuable alternative or supplement to PT in facilitating BT effects. Notably, IMIT is preferable to EMIT, and interventions incorporating tasks that have access to both intrinsic and extrinsic coordinates (mixed-task) are preferred over those that involve only one of the two coordinates (mirror-task or normal-task). These findings have implications for rehabilitation of patients such as stroke survivors
Properties of Light Flavour Baryons in Hypercentral quark model
The light flavour baryons are studied within the quark model using the hyper
central description of the three-body system. The confinement potential is
assumed as hypercentral coulomb plus power potential () with power
index . The masses and magnetic moments of light flavour baryons are
computed for different power index, starting from 0.5 to 1.5. The
predicted masses and magnetic moments are found to attain a saturated value
with respect to variation in beyond the power index 1.0. Further
we computed transition magnetic moments and radiative decay width of light
flavour baryons. The results are in good agreement with known experimental as
well as other theoretical models.Comment: Accepted in Pramana J. of Physic
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