Finite-quasiparticle-lifetime effects in the differential conductance ofBi2Sr2CaCu2Oy/Au junctions

1994 ◽  
Vol 49 (14) ◽  
pp. 10016-10019 ◽  
Author(s):  
A. Pleceník ◽  
M. Grajcar ◽  
Š. Beňačka ◽  
P. Seidel ◽  
A. Pfuch
Keyword(s):  
Differential Conductance ◽  
Quasiparticle Lifetime ◽  
Lifetime Effects

scholarly journals NanoLEDs for energy-efficient and gigahertz-speed spike-based sub-λ neuromorphic nanophotonic computing

Nanophotonics ◽  
2020 ◽  
Vol 9 (13) ◽  
pp. 4149-4162 ◽  
Author(s):  
Bruno Romeira ◽  
José M. L. Figueiredo ◽  
Julien Javaloyes
Keyword(s):  
Neural Networks ◽  
Energy Efficient ◽  
High Speed ◽  
Dynamic Properties ◽  
Optical Computing ◽  
Differential Conductance ◽  
Rate Equations ◽  
Dynamical Equations ◽  
Electrical Modulation ◽  
High Bandwidth

AbstractEvent-activated biological-inspired subwavelength (sub-λ) photonic neural networks are of key importance for future energy-efficient and high-bandwidth artificial intelligence systems. However, a miniaturized light-emitting nanosource for spike-based operation of interest for neuromorphic optical computing is still lacking. In this work, we propose and theoretically analyze a novel nanoscale nanophotonic neuron circuit. It is formed by a quantum resonant tunneling (QRT) nanostructure monolithic integrated into a sub-λ metal-cavity nanolight-emitting diode (nanoLED). The resulting optical nanosource displays a negative differential conductance which controls the all-or-nothing optical spiking response of the nanoLED. Here we demonstrate efficient activation of the spiking response via high-speed nonlinear electrical modulation of the nanoLED. A model that combines the dynamical equations of the circuit which considers the nonlinear voltage-controlled current characteristic, and rate equations that takes into account the Purcell enhancement of the spontaneous emission, is used to provide a theoretical framework to investigate the optical spiking dynamic properties of the neuromorphic nanoLED. We show inhibitory- and excitatory-like optical spikes at multi-gigahertz speeds can be achieved upon receiving exceptionally low (sub-10 mV) synaptic-like electrical activation signals, lower than biological voltages of 100 mV, and with remarkably low energy consumption, in the range of 10–100 fJ per emitted spike. Importantly, the energy per spike is roughly constant and almost independent of the incoming modulating frequency signal, which is markedly different from conventional current modulation schemes. This method of spike generation in neuromorphic nanoLED devices paves the way for sub-λ incoherent neural elements for fast and efficient asynchronous neural computation in photonic spiking neural networks.

scholarly journals An obstacle to sub-AdS holography for SYK-like models

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Pengfei Zhang ◽  
Yingfei Gu ◽  
Alexei Kitaev
Keyword(s):  
Lyapunov Exponent ◽  
Weak Coupling ◽  
Kinetic Coefficient ◽  
Weak Coupling Limit ◽  
Branching Time ◽  
Quasiparticle Lifetime

Abstract We argue that “stringy” effects in a putative gravity-dual picture for SYK-like models are related to the branching time, a kinetic coefficient defined in terms of the retarded kernel. A bound on the branching time is established assuming that the leading diagrams are ladders with thin rungs. Thus, such models are unlikely candidates for sub-AdS holography. In the weak coupling limit, we derive a relation between the branching time, the Lyapunov exponent, and the quasiparticle lifetime using two different approximations.

New Approach to Negative Differential Conductance with High Peak-to-Valley Ratio in Silicon

2000 ◽  
Vol 39 (Part 1, No. 4B) ◽  
pp. 2246-2250 ◽  
Author(s):  
Junji Koga ◽  
Celine Vanderstraeten ◽  
Shin-ichi Takagi ◽  
Akira Toriumi
Keyword(s):  
High Peak ◽  
Differential Conductance ◽  
Negative Differential Conductance ◽  
New Approach ◽  
Peak To Valley Ratio

Ultrafast Electron−Optical Phonon Scattering and Quasiparticle Lifetime in CVD-Grown Graphene

ACS Nano ◽  
2011 ◽  
Vol 5 (4) ◽  
pp. 3278-3283 ◽  
Author(s):  
Jingzhi Shang ◽  
Ting Yu ◽  
Jianyi Lin ◽  
Gagik G. Gurzadyan
Keyword(s):  
Optical Phonon ◽  
Phonon Scattering ◽  
Optical Phonon Scattering ◽  
Quasiparticle Lifetime ◽  
Grown Graphene
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