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Results for “hopping”
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Interorbital antisymmetric hopping generated flat bands on kagome and pyrochlore Lattices
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Surface hopping molecular dynamics simulation of ultrafast methyl iodide photodissociation mapped by Coulomb explosion imaging
Our simulation demonstrates the robustness of the Coulomb explosion imaging technique in studying methyl iodide photodissociation, and shows that it can be effectively used for imaging non-adiabatic transitions in coordinate space.
Hopping mediated transport between finite pools of redox proteins
Transport reactions in biology involve the flow of particles—electrons, ions, or molecules—between reservoirs. Here, we explore how electron transport between finite reservoirs depends on the nature of the reservoirs, including their size, occupancy, and interactions. We compare the transport kinetics produced by narrowband and wideband infinite reservoir models (described earlier) with a finite narrowband reservoir model. The transport between finite reservoirs is found to depend on both the initial charge distribution and the number of carriers present. Whether or not a steady-state transport regime is accessed prior to reaching the equilibrium charge distribution depends on these initial conditions.
Recovery of a Luther-Emery phase in the three-band Hubbard ladder with longer-range hopping
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Untangling the Broadening of Adiabatic Cloud Droplet Spectra through Eddy Hopping in a High-Resolution Cumulus Congestus Simulation
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Broadening of Adiabatic Droplet Spectra through Eddy Hopping: Polluted versus Pristine Environments
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Tilted stripes origin in La1.88Sr0.12CuO4 revealed by anisotropic next-nearest neighbor hopping
Phase diagram of high-Tc cuprate superconductors
The Kangaroo’s First Hop: The Early Fast Cooling Phase of EP250108a/SN 2025kg
Fast X-ray transients are a rare and poorly understood population of events. Previously difficult to detect in real time, the launch of the Einstein Probe with its Wide-field X-ray Telescope has led to a rapid expansionof the sample and allowed the exploration of these transients across the electromagnetic spectrum. EP250108a is a recently detected example linked to an optical counterpart, SN 2025kg, or “the kangaroo.” Together with a companion Letter we present our observing campaign and analysis of this event. In this letter, we focus on the early evolution of the optical counterpart over the first 6 days, including our measurement of the redshift of z = 0.17641. We compare to other supernovae and fast transients showing similar features, finding significant similarities with SN 2006aj and SN 2020bvc, and show that the source is well modelled by a rapidly expanding cooling blackbody. We show the observed X-ray and radio properties are consistent with a collapsar-powered jet that is low energy (≲10 51 erg) and/or fails to break out of the dense material surrounding it. While we examine the possibility that the optical emission emerges from the shock produced as the supernova ejecta expand into a dense shell of circumstellar material, due to our X-ray and radio inferences, we favour a model where it arises from a shocked cocoon resulting from a trapped jet. This makes SN 2025 one of the few examples of this currently observationally rare event.
Coherent detection of frequency-hopped quadrature modulations in the presence of jamming. I - QPSK and QASK modulations
This paper examines the performance of coherent QPSK and QASK systems combined with FH or FH/PN spread spectrum techniques in the presence of partial-band multitone or noise jamming. The worst-case jammer and worst-case performance are determined as functions of the signal-to-background noise ratio (SNR) and signal-to-jammer power ratio (SJR). Asymptotic results for high SNR are shown to have a linear dependence between the jammer's optimal power allocation and the system error probability performance.
Coherent detection of frequency-hopped quadrature modulations in the presence of jamming. II - QPR Class I modulation
This paper considers the performance of quadrature partial response (QPR) in the presence of jamming. Although a QPR system employs a single sample detector in its receiver, while quadrature amplitude shift keying (or quadrature phase shift keying) requires a matched-filter type of receiver, it is shown that the coherent detection performances of the two in the presence of the intentional jammer have definite similarities.
Switches, lasers and electronically-hopped beam antennas in space - NASA's advanced communications technology satellite
The proposed design and operation of the Advanced Communications Technology Satellite (ACTS) are described. The ACTS is a three-axis stabilized spacecraft with an in-orbit weight of 2300 lbs and a beginning-of-life power of 1770 W; it is composed of a 20 GHz 2.2 m downlink antenna, a 30 GHz 3.3 m uplink antenna, a 1 m steerable antenna, and a laser package. The space segment communications payload uses high and low burst rate modes; the operations of these modes are discussed. The components of the laser intersatellite link instrument package are examined. Consideration is given to the ACTS's antennas, RF matrix switch system, and the base band processor. Diagrams of the ACTs systems are presented.
Tuning Monotonic Basin Hopping: Improving the Efficiency of Stochastic Search as Applied to Low-Thrust Trajectory Optimization
Trajectory optimization methods using MBH have become well developed during the past decade. An essential component of MBH is a controlled random search through the multi-dimensional space of possible solutions. Historically, the randomness has been generated by drawing RVs from a uniform probability distribution. Here, we investigate the generating the randomness by drawing the RVs from Cauchy and Pareto distributions, chosen because of their characteristic long tails. We demonstrate that using Cauchy distributions (as first suggested by Englander significantly improves MBH performance, and that Pareto distributions provide even greater improvements. Improved performance is defined in terms of efficiency and robustness, where efficiency is finding better solutions in less time, and robustness is efficiency that is undiminished by (a) the boundary conditions and internal constraints of the optimization problem being solved, and (b) by variations in the parameters of the probability distribution. Robustness is important for achieving performance improvements that are not problem specific. In this work we show that the performance improvements are the result of how these long-tailed distributions enable MBH to search the solution space faster and more thoroughly. In developing this explanation, we use the concepts of sub-diffusive, normally-diffusive, and super-diffusive RWs originally developed in the field of statistical physics.
Gravity Hoppers: hopping probes for the interior map of small solar system bodies
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Gravity Poppers: Hopping Probes for the Interior Mapping of Small Solar System Bodies
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ILLUMA-T: First Demonstration of Multi-Hop Lasercom Link to/from ISS to Ground
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Quantities of Ballistically Hopping Water Molecules on the Moon: Consistent With Exospheric Hydration Observations
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