Giant vacuum friction: PT symmetric spectral singularity and negative frequency resonance (Conference Presentation)

2017 ◽  
Author(s):  
Sarang Pendharker ◽  
Yu Guo ◽  
Farhad Khosravi ◽  
Zubin Jacob
Keyword(s):  
Spectral Singularity ◽  
Frequency Resonance

scholarly journals PT-symmetric spectral singularity and negative-frequency resonance

2017 ◽  
Vol 95 (3) ◽  
Author(s):  
Sarang Pendharker ◽  
Yu Guo ◽  
Farhad Khosravi ◽  
Zubin Jacob
Keyword(s):  
Spectral Singularity ◽  
Frequency Resonance

Theta-Frequency Resonance in Hippocampal CA1 Neurons In Vitro Demonstrated by Sinusoidal Current Injection

1998 ◽  
Vol 79 (3) ◽  
pp. 1592-1596 ◽  
Author(s):  
L. Stan Leung ◽  
Hui-Wen Yu
Keyword(s):  
Resonant Frequency ◽  
Hippocampal Neurons ◽  
Ca1 Neurons ◽  
Frequency Resonance ◽  
Hippocampal Ca1 Neurons ◽  
Hippocampal Ca1 ◽  
Theta Frequency ◽  
Sinusoidal Current ◽  
Sinusoidal Currents

Leung, L. Stan and Hui-Wen Yu. Theta-frequency resonance in hippocampal CA1 neurons in vitro demonstrated by sinusoidal current injection. J. Neurophysiol. 79: 1592–1596, 1998. Sinusoidal currents of various frequencies were injected into hippocampal CA1 neurons in vitro, and the membrane potential responses were analyzed by cross power spectral analysis. Sinusoidal currents induced a maximal (resonant) response at a theta frequency (3–10 Hz) in slightly depolarized neurons. As predicted by linear systems theory, the resonant frequency was about the same as the natural (spontaneous) oscillation frequency. However, in some cases, the resonant frequency was higher than the spontaneous oscillation frequency, or resonance was found in the absence of spontaneous oscillations. The sharpness of the resonance ( Q), measured by the peak frequency divided by the half-peak power bandwidth, increased from a mean of 0.44 at rest to 0.83 during a mean depolarization of 6.5 mV. The phase of the driven oscillations changed most rapidly near the resonant frequency, and it shifted about 90° over the half-peak bandwidth of 8.4 Hz. Similar results were found using a sinusoidal function of slowly changing frequency as the input. Sinusoidal currents of peak-to-peak intensity of >100 pA may evoke nonlinear responses characterized by second and higher harmonics. The theta-frequency resonance in hippocampal neurons in vitro suggests that the same voltage-dependent phenomenon may be important in enhancing a theta-frequency response when hippocampal neurons are driven by medial septal or other inputs in vivo.

scholarly journals Very-low-frequency resonance of MOSFET amplifier parameters

1994 ◽  
Vol 37 (10) ◽  
pp. 1739-1751 ◽  
Author(s):  
O.L. Yakymakha ◽  
Y.M. Kalnibolotskij
Keyword(s):  
Low Frequency ◽  
Very Low Frequency ◽  
Frequency Resonance
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