6,070 research outputs found
Virtual contributions from and in the decays
We study the quasi-two-body decays with
in the perturbative QCD approach and focus on the virtual contributions from
the off-shell and in the four
measured decays , , and . For the and
decays, their branching fractions concentrate in a very small region of
near pole mass, and the virtual contributions from
, in the region GeV, are about of the
corresponding quasi-two-body results. We define two ratios and
, from which we conclude that the flavor- symmetry will be
maintained for the decays with very small breaking at
any physical value of the . The
and decays can be employed as a constraint
for the decay width, with preferred values consistent with previous
theoretical predictions for this quantity.Comment: 12 pages, 5 figures. Published versio
Impact of Edge States on Device Performance of Phosphorene Heterojunction Tunneling Field Effect Transistors
Black phosphorus (BP) tunneling transistors (TFETs) using heterojunction (He)
are investigated by atomistic quantum transport simulations. It is observed
that edge states have a great impact on transport characteristics of BP
He-TFETs, which result in the potential pinning effect and deteriorate the gate
control. While, on-state current can be effectively enhanced by using hydrogen
to saturate the edge dangling bonds in BP He-TFETs, in which edge states are
quenched. By extending layered BP with a smaller band gap to the channel region
and modulating the BP thickness, device performance of BP He-TFETs can be
further optimized and fulfill the requirements of the international technology
road-map for semiconductors (ITRS) 2013 for low power applications. In 15 nm
3L-1L and 4L-1L BP He-TFETs along armchair direction on-state current can reach
above 10 A/m with the fixed off-state current of 10 m. It
is also found that ambipolar effect can be effectively suppressed in BP
He-TFETs.Comment: 12 pages, 5 figure
Extremely long-lived universal resonant Bose gases
Quantum simulations based on near-resonance Bose gases are limited by their
short lifetimes due to severe atom losses. In addition to this, the recently
predicted thermodynamical instability adds another constraint on accessing the
resonant Bose gases. In this Letter, we offer a potential solution by proposing
long-lived resonant Bose gases in both two and three dimensions, where the
conventional few-body losses are strongly suppressed. We show that the
thermodynamical properties as well as the lifetimes of these strongly
interacting systems are universal, and independent of short-range physics.Comment: 5 page
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