Eternal inflation when in the presence of dissipation and quantum and thermal noise effects

2017 ◽  
Author(s):  
Rudnei O. Ramos ◽  
Gustavo S. Vicente ◽  
Leandro A. da Silva
Keyword(s):  
Thermal Noise ◽  
Noise Effects ◽  
Eternal Inflation

BEHAVIOR OF DOUBLE JUNCTION SQUID OF Y-Ba-Cu-O BULK SUPERCONDUCTOR

1989 ◽  
Vol 03 (06) ◽  
pp. 519-524 ◽  
Author(s):  
N.D. KATARIA ◽  
V.S. TOMAR ◽  
V.N. OJHA ◽  
MUKESH KUMAR ◽  
G.S.N. REDDY ◽  
...  
Keyword(s):  
Thermal Noise ◽  
The Self ◽  
Bulk Superconductor ◽  
Noise Effects ◽  
Double Junction ◽  
Parallel Arrays

A dc SQUID like geometry with a ring and a pair of constrictions is carved out of bulk Y-Ba-Cu-O superconductor. The I—V curves exhibit hysteresis arising due to trapping of the self fields. The V—Φ curves show multiple flux periodicities with unequal amplitudes. There is twenty fold rise in the amplitude of voltage modulation in cooling from 77 to 4.2 K. The complications of presence of series and parallel arrays of granular junctions are attributed respectively to large and small periodicities observed in V—Φ curves. The modulation structure gets more resolved at 4.2 K due to reduction in thermal noise effects.

ASYMMETRIC DC-SQUIDS: MAGNETIC AND NOISE PROPERTIES

2000 ◽  
Vol 14 (25n27) ◽  
pp. 3062-3067
Author(s):  
G. TESTA ◽  
S. PAGANO ◽  
E. SARNELLI ◽  
C. R. CALIDONNA ◽  
M. RUSSO ◽  
...  
Keyword(s):  
Critical Temperature ◽  
Transfer Function ◽  
Magnetic Flux ◽  
High Performance ◽  
Thermal Noise ◽  
Bias Current ◽  
Device Performance ◽  
Noise Effects ◽  
Normal Resistance ◽  
High Performance Computer

SQUID configurations with an asymmetry in both the critical current and the normal resistance of the two Josephson junctions have been numerically analyzed. The analysis has been carried out on a high performance computer, by choosing parameters typical of low critical temperature SQUIDs. In particular the dependence of both the magnetic flux noise S Φ and the flux to voltage transfer function V Φ on the bias current and the normalized SQUID inductance β have been investigated. Thermal noise effects, including contributions of both junction and damping resistance have been introduced in the calculations. The results show that an increase of the asymmetry leads to higher V Φ and lower S Φ values. This suggests to use asymmetric dc-SQUIDs to improve the device performance for both small and large inductance values.

Comparative Simulation of Thermal Noise Effects for Photodetectors on Performance of Long-Haul DWDM Optical Networks

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
I. S. Amiri ◽  
Fatma Mohammed Aref Mahmoud Houssien ◽  
Ahmed Nabih Zaki Rashed ◽  
Abd El-Naser A. Mohammed
Keyword(s):  
Optical Networks ◽  
Wavelength Division Multiplexing ◽  
Thermal Noise ◽  
Signal To Noise Ratio ◽  
Avalanche Photodiode ◽  
Input Power ◽  
Superior Performance ◽  
Noise Effects ◽  
Wavelength Division ◽  
The Impact

AbstractLong-haul 16-channel dense-wavelength division multiplexing networks employing two different avalanche photodiode (APD) structures (Si and InGaAs) and positive-intrinsic-negative (PIN) photodetectors are simulated and compared under thermal noise effects for different fiber lengths. The effect of thermal noise level on the transmission quality with a variation of amplifying section length, number of amplifying sections and channel speed is discussed. The impact of thermal noise on the system performance is analyzed by varying input power from −5dBm to 20dBm for both 25 km and 50 km amplifying section at 100 km fiber length. The performance is evaluated for both 5 Gb/s and 10 Gb/s data rates over transmission distances up to 500 km. A comprehensive comparison is developed based on signal-to-noise ratio (SNR), quality factor (Q-factor) and bit error rate (BER). It is found that both APD structures achieve superior performance up to distance of 350 km comparing to PIN photodetectors for 50 km amplifying section. The system provides optimum performance at input power Pin = 10dBm in case of 50 km amplifying section, but then afterwards, the performance is degraded rapidly due to nonlinearities. The results revealed that the worst performance scenario is at 10–18 W/Hz thermal noise in terms of higher BER and lower Q-factor. Finally, the desirable BER of 10–12 is achieved at Q-factor of 6.78 and SNR of 23 dB.

Ultra-spatially resolved synchrotron powered FT-IR microspectroscopy of individual cells of biological material

1995 ◽  
Vol 53 ◽  
pp. 884-885
Author(s):  
David L. Wetzel ◽  
John A. Reffner ◽  
Gwyn P. Williams
Keyword(s):  
Thermal Noise ◽  
Spot Size ◽  
Acquisition Time ◽  
Thermal Source ◽  
Signal To Noise ◽  
Spatially Resolved ◽  
Good Spatial Resolution ◽  
Small Spot ◽  
Ft Ir ◽  
Ir Microspectroscopy

Synchrotron radiation is 100 to 1000 times brighter than a thermal source such as a globar. It is not accompanied with thermal noise and it is highly directional and nondivergent. For these reasons, it is well suited for ultra-spatially resolved FT-IR microspectroscopy. In efforts to attain good spatial resolution in FT-IR microspectroscopy with a thermal source, a considerable fraction of the infrared beam focused onto the specimen is lost when projected remote apertures are used to achieve a small spot size. This is the case because of divergence in the beam from that source. Also the brightness is limited and it is necessary to compromise on the signal-to-noise or to expect a long acquisition time from coadding many scans. A synchrotron powered FT-IR Microspectrometer does not suffer from this effect. Since most of the unaperatured beam’s energy makes it through even a 12 × 12 μm aperture, that is a starting place for aperture dimension reduction.

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