3,853 research outputs found
Electromechanical Quantum Simulators
Digital quantum simulators are among the most appealing applications of a
quantum computer. Here we propose a universal, scalable, and integrated quantum
computing platform based on tunable nonlinear electromechanical
nano-oscillators. It is shown that very high operational fidelities for single
and two qubits gates can be achieved in a minimal architecture, where qubits
are encoded in the anharmonic vibrational modes of mechanical nanoresonators,
whose effective coupling is mediated by virtual fluctuations of an intermediate
superconducting artificial atom. An effective scheme to induce large
single-phonon nonlinearities in nano-electromechanical devices is explicitly
discussed, thus opening the route to experimental investigation in this
direction. Finally, we explicitly show the very high fidelities that can be
reached for the digital quantum simulation of model Hamiltonians, by using
realistic experimental parameters in state-of-the art devices, and considering
the transverse field Ising model as a paradigmatic example.Comment: 14 pages, 8 figure
Magnetism and pairing of two-dimensional trapped fermions
The emergence of local phases in a trapped two-component Fermi gas in an
optical lattice is studied using quantum Monte Carlo simulations. We treat
temperatures that are comparable or lower than those presently achievable in
experiments and large enough systems that both magnetic and paired phases can
be detected by inspection of the behavior of suitable short-range correlations.
We use the latter to suggest the interaction strength and temperature range at
which experimental observation of incipient magnetism and d-wave pairing are
more likely and evaluate the relation between entropy and temperature in
two-dimensional confined fermionic systems.Comment: 4 pages + supplementary materia
Rational and affordable concepts of Landing Gear for small reentry vehicle demonstrators
The paper proposes an innovative solution for landing gear of small space vehicles, in particular of technological demonstrators of reentry space vehicles. After explaining why small space vehicles can benefit from landing gears, the work investigates a solution, which avoids the use of fluidic systems and minimizes constraints on the whole vehicle, thus limiting cost raising and making the installation of the landing gear easier on vehicles that originally did not envisage landing gears
Optimized Confinement of Fermions in Two Dimensions
One of the challenging features of studying model Hamiltonians with cold
atoms in optical lattices is the presence of spatial inhomogeneities induced by
the confining potential, which results in the coexistence of different phases.
This paper presents Quantum Monte Carlo results comparing meth- ods for
confining fermions in two dimensions, including conventional diagonal
confinement (DC), a recently proposed 'off-diagonal confinement' (ODC), as well
as a trap which produces uniform den- sity in the lattice. At constant entropy
and for currently accessible temperatures, we show that the current DC method
results in the strongest magnetic signature, primarily because of its judicious
use of entropy sinks at the lattice edge. For d-wave pairing, we show that a
constant density trap has the more robust signal and that ODC can implement a
constant density profile. This feature is important to any prospective search
for superconductivity in optical lattices
Slow breathing and hypoxic challenge: cardiorespiratory consequences and their central neural substrates
Controlled slow breathing (at 6/min, a rate frequently adopted during yoga practice) can benefit cardiovascular function, including responses to hypoxia. We tested the neural substrates of cardiorespiratory control in humans during volitional controlled breathing and hypoxic challenge using functional magnetic resonance imaging (fMRI). Twenty healthy volunteers were scanned during paced (slow and normal rate) breathing and during spontaneous breathing of normoxic and hypoxic (13% inspired O2) air. Cardiovascular and respiratory measures were acquired concurrently, including beat-to-beat blood pressure from a subset of participants (N = 7). Slow breathing was associated with increased tidal ventilatory volume. Induced hypoxia raised heart rate and suppressed heart rate variability. Within the brain, slow breathing activated dorsal pons, periaqueductal grey matter, cerebellum, hypothalamus, thalamus and lateral and anterior insular cortices. Blocks of hypoxia activated mid pons, bilateral amygdalae, anterior insular and occipitotemporal cortices. Interaction between slow breathing and hypoxia was expressed in ventral striatal and frontal polar activity. Across conditions, within brainstem, dorsal medullary and pontine activity correlated with tidal volume and inversely with heart rate. Activity in rostroventral medulla correlated with beat-to-beat blood pressure and heart rate variability. Widespread insula and striatal activity tracked decreases in heart rate, while subregions of insular cortex correlated with momentary increases in tidal volume. Our findings define slow breathing effects on central and cardiovascular responses to hypoxic challenge. They highlight the recruitment of discrete brainstem nuclei to cardiorespiratory control, and the engagement of corticostriatal circuitry in support of physiological responses that accompany breathing regulation during hypoxic challenge
Coping with negative stereotypes toward older workers: Organizational and work-related outcomes
The current study aims to test a moderated-mediation model in which occupational selfefficacy determines the indirect effect of negative stereotypes about older workers in the organization both on psychological engagement in the work domain and on attitudes toward development opportunities through identification with the company. The survey involved 1,501 Italian subjects aged over 50 who were employed by a major large-scale retailer. Consistently with the Social Identity Theory and the Social Exchange Theory, results showed that the perception of negative stereotypes about older workers in the organization is associated with low identification with the company and, subsequently, with poor psychological engagement in the work domain and with attitudes indicating very little interest in development opportunities. In addition, this association was found to be stronger in older workers with higher and medium levels of occupational selfefficacy. These findings suggest that organizations should discourage the dissemination of negative stereotypes about older workers in the workplace because they may lead to older workers' disengagement from the work domain and their loss of interest in development opportunities
A new technique for direct investigation of dark matter
The MOSCAB experiment (Materia OSCura A Bolle) uses a new technique for Dark
Matter search. The Geyser technique is applied to the construction of a
prototype detector with a mass of 0.5 kg and the encouraging results are
reported here; an accent is placed on a big detector of 40 kg in construction
at the Milano-Bicocca University and INFN
The role of feedback on interview self-efficacy and outcome expectations
Applicants’ self-cognitions toward selection procedures are decisive to produce favorable outcomes. Drawing upon the career self-management model, this study explored the impact of performance feedback after a simulated employment interview on interview self-efficacy (ISE) and outcome expectations. Participants (a sample of recent graduates; N = 240) were given timely feedback after the simulated interview with suggestions to improve their performance. The interviewer’s feedback was positively related to participants’ ISE measured after the feedback. A significant relationship between participants’ ISE and outcome expectations emerged. Feedback was related to outcome expectations only indirectly, via ISE. This study contributes to existing knowledge about ISE and provides practitioners with hints to help job seekers to master job search in troubled times. Practitioner notes Interview self-efficacy is a major predictor of performance in the employment interview. We show that performance feedback enhances interview self-efficacy and outcome expectations. Job seekers in training should be given meaningful feedback to raise their interview self-efficacy
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