4,508 research outputs found
Andreev Probe of Persistent Current States in Superconducting Quantum Circuits
Using the extraordinary sensitivity of Andreev interferometers to the
superconducting phase difference associated with currents, we measure the
persistent current quantum states in superconducting loops interrupted by
Josephson junctions. Straightforward electrical resistance measurements of the
interferometers give continuous read-out of the states, allowing us to
construct the energy spectrum of the quantum circuit. The probe is estimated to
be more precise and faster than previous methods, and can measure the local
phase difference in a wide range of superconducting circuits.Comment: Changes made in light of referees comments; to appear in PR
Further investigation on chaos of real digital filters
This Letter displays, via the numerical simulation of a real digital filter, that a finite-state machine may behave in a near-chaotic way even when its corresponding infinite-state machine does not exhibit chaotic behavior
Control of Multi-level Voltage States in a Hysteretic SQUID Ring-Resonator System
In this paper we study numerical solutions to the quasi-classical equations
of motion for a SQUID ring-radio frequency (rf) resonator system in the regime
where the ring is highly hysteretic. In line with experiment, we show that for
a suitable choice of of ring circuit parameters the solutions to these
equations of motion comprise sets of levels in the rf voltage-current dynamics
of the coupled system. We further demonstrate that transitions, both up and
down, between these levels can be controlled by voltage pulses applied to the
system, thus opening up the possibility of high order (e.g. 10 state),
multi-level logic and memory.Comment: 8 pages, 9 figure
Novel battery thermal management via scalable dew-point evaporative cooling
Thermal management is critical to safety, stability, and durability of battery energy storage systems. Existing passive and active air cooling are not competent when the cooling performance, energy efficiency and cost of the thermal management system are drawing concurrent concerns. Here we propose dew-point evaporative cooling as a novel active air-cooling approach for large battery systems. Its capability of cooling the air towards its dew-point temperature with simple working principle and great electrical efficiency offers an ideal solution. Therefore, a scalable dew-point evaporative cooling technology was developed, and a large-scale cooler was constructed which could deliver 2.9–6.7 kW cooling capacity with 8.9–28.9 coefficient of performance (COP). To demonstrate its performance for battery thermal management, we took a 20 Ah lithium iron phosphate (LFP) prismatic pouch cells for a case study whose complex dynamic electrochemical and thermal responses were investigated via lock-in thermography experiments and electrochemical-thermal modeling. The potential of dew-point evaporative cooling for battery cooling was explored via the multi-physics coupling of battery and cooler models. This study elucidates that dew-point evaporative cooling can efficiently cool a battery by 3.0–13.6 °C lower than the cases with only forced convection, and control the battery operating temperature within an ideal operating range of 20–40 °C
Evidence for Factorization in Three-body B --> D(*) K- K0 Decays
Motivated by recent experimental results, we use a factorization approach to
study the three-body B --> D(*) K- K0 decay modes. Two mechanisms are proposed
for kaon pair production: current-produced (from vacuum) and transition (from B
meson). The Bbar0 --> D(*)+ K- K0 decay is governed solely by the
current-produced mechanism. As the kaon pair can be produced only by the vector
current, the matrix element can be extracted from e+ e- --> K Kbar processes
via isospin relations. The decay rates obtained this way are in good agreement
with experiment. Both current-produced and transition processes contribute to
B- --> D(*)0 K- K0 decays. By using QCD counting rules and the measured B- -->
D(*)0 K- K0 decay rates, the measured decay spectra can be understood.Comment: 17 pages, 6 figure
Phenomenological Consequences of Right-handed Down Squark Mixings
The mixings of quarks, hidden from view in Standard Model (SM), are
naturally the largest if one has an Abelian flavor symmetry. With supersymmetry
(SUSY) their effects can surface via squark loops. Squark and
gluino masses are at TeV scale, but they can still induce effects comparable to
SM in (or ) mixings, while mixing could be close to recent
hints from data. In general, CP phases would be different from SM, as may be
indicated by recent B Factory data. Presence of non-standard soft SUSY
breakings with large could enhance (or )
transitions.Comment: Version to appear in Phys. Rev. Let
Charmless Three-Body Baryonic B Decays
Motivated by recent data on B-> p pbar K decay, we study various charmless
three-body baryonic B decay modes, including Lambda pbar pi, Sigma0 pbar pi, p
pbar pi, p pbar Kbar0, in a factorization approach. These modes have rates of
order 10^{-6}. There are two mechanisms for the baryon pair production,
current-produced and transition. The behavior of decay spectra from these
baryon production mechanisms can be understood by using QCD counting rules.
Predictions on rates and decay spectra can be checked in the near future.Comment: 26 pages, 9 figures; version to appear in Phys. Rev.
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