### 21982 results for qubit oscillator frequency

Contributors: Yoshihiro Maegaki, Imad Najm, Kiyohito Terada, Harold H Morris, William E Bingaman, Norimasa Kohaya, Atsumi Takenobu, Yoko Kadonaga, Hans O Lüders

Date: 2000-01-01

Cortical distributions of SEPs and high-**frequency** **oscillations** to median nerve stimulation in Patient 5. (A) Typical high-**frequency** **oscillation** potential recorded at electrode A5. (B) The location of recording electrodes. (C) Cortical distributions of the SEPs and high-**frequency** **oscillations**. P20/N20 are distributed diffusely around the primary hand sensorimotor area, while P25 is elicited in a restricted cortical area. Most **oscillation** potentials show a cortical distribution similar to that of P20/N20. Two later **oscillations** (n21 and p22) are elicited in a restricted cortical area similar to P25.
...Typical examples of high-**frequency** **oscillations** to median nerve stimulation recorded with a restricted bandpass filter of 500–2000 Hz compared with SEPs recorded with a wide bandpass filter of 30–2000 Hz. The SEPs and high-**frequency** **oscillations** were recorded at the same precentral electrodes (A1 in Patient 2 and A5 in Patient 5). Note the better isolated **oscillation** potentials on restricted filtering as a result of the attenuation of slower SEP components. Most of the **oscillation** potentials can be identified with both bandpass filters. p22 can only be seen on restricted bandpass filtering in Patient 2. The latencies of **oscillations** differed by 0.11 ms for the two different bandpass filters.
...Clinical and imaging characteristics of 8 patients for whom high-**frequency** **oscillations** were evaluateda
...Cortical distributions of SEPs and high-**frequency** **oscillations** to median nerve stimulation in Patient 7. (A) Typical high-**frequency** **oscillation** potential recorded at electrode C1. (B) The location of recording electrodes on the 3-dimensional MRI reconstruction. (C) Cortical distributions of the SEPs and high-**frequency** **oscillations**. Most **oscillation** potentials are distributed similar to or more diffusely than P20/N20. Three later **oscillations** (n18, p18 and n19) are elicited in a restricted cortical area similar to P25.
...High-**frequency** **oscillation**...Objective: To elucidate the generator sources of high-**frequency** **oscillations** of somatosensory evoked potentials (SEPs), we recorded somatosensory evoked high-**frequency** **oscillations** directly from the human cerebral cortex....The locations of the subdural electrode array and functional brain mapping in each patient. SEPs and high-**frequency** **oscillations** were recorded from the electrodes enclosed by solid lines. Electrodes A7 and C4, and A4 were not used for recording because of disconnection of the wires in Patients 5 and 7, respectively. CS, central sulcus.
... Objective: To elucidate the generator sources of high-**frequency** **oscillations** of somatosensory evoked potentials (SEPs), we recorded somatosensory evoked high-**frequency** **oscillations** directly from the human cerebral cortex.

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Contributors: J.C. Cao, X.L. Lei, H.C. Liu

Date: 2003-11-01

We have theoretically investigated spatiotemporal current patterns and self-**oscillating** characteristics of negative-effective-mass (NEM) p+pp+ diodes. Periodically **oscillating** current densities are presented as a gray density plot, showing rich patterns with the applied bias and doping concentration as controlling parameters. Such a pattern arises in the NEM p-base with a “N-shaped” velocity–field relation. Two-dimensional applied bias-doping concentration phase diagrams at different lattice temperatures are calculated in order to visualize the effect of lattice temperature on the self-**oscillating** regions. It is indicated that both the applied bias and the doping concentration strongly influence the patterns and self-**oscillating** **frequencies**, which are generally in the terahertz (THz) **frequency** band. The NEM p+pp+ diode may therefore be used to develop a electrically tunable THz-**frequency** **oscillator**....Self-**oscillation**...Time-periodic self-**oscillating** current densities for the p+pp+ NEM diodes at T=77 K and doping concentrations Na=7×1016 cm−3 are shown as a density gray plot, where lighter areas correspond to larger amplitudes of the current densities.
...Self-**oscillating** **frequencies** of the p+pp+ NEM diodes at T=77 K with four doping concentrations indicated by the arrows in Fig. 2(a): (a) Na=7×1016 cm−3 and (b) Na=4.5×1017 cm−3, respectively.
...Applied bias-doping concentration phase diagrams of current self-**oscillations** in the p+pp+ NEM diodes at four lattice temperatures: (a) T=77 K, (b) 145 K, (c) 180 K, and (d) 220 K, respectively. Throughout the paper, the p-base length is set to be l=0.3μm, and the doping concentration in the contact p+-region is assumed to be 2×1018 cm−3.
... We have theoretically investigated spatiotemporal current patterns and self-**oscillating** characteristics of negative-effective-mass (NEM) p+pp+ diodes. Periodically **oscillating** current densities are presented as a gray density plot, showing rich patterns with the applied bias and doping concentration as controlling parameters. Such a pattern arises in the NEM p-base with a “N-shaped” velocity–field relation. Two-dimensional applied bias-doping concentration phase diagrams at different lattice temperatures are calculated in order to visualize the effect of lattice temperature on the self-**oscillating** regions. It is indicated that both the applied bias and the doping concentration strongly influence the patterns and self-**oscillating** **frequencies**, which are generally in the terahertz (THz) **frequency** band. The NEM p+pp+ diode may therefore be used to develop a electrically tunable THz-**frequency** **oscillator**.

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Contributors: Lucas C. Monteiro, A.V. Dodonov

Date: 2016-04-08

We consider the interaction between a single cavity mode and N≫1 identical **qubits**, assuming that any system parameter can be rapidly modulated in situ by external bias. It is shown that, for the **qubits** initially in the ground states, three photons can be coherently annihilated in the dispersive regime for harmonic modulation with **frequency** 3ω0−Ω0, where ω0 (Ω0) is the bare cavity (**qubit**) **frequency**. This phenomenon can be called “Anti-dynamical Casimir effect”, since a pair of excitations is destroyed without dissipation due to the external modulation. For the initial vacuum cavity state, three **qubit** excitations can also be annihilated for the modulation **frequency** 3Ω0−ω0. ... We consider the interaction between a single cavity mode and N≫1 identical **qubits**, assuming that any system parameter can be rapidly modulated in situ by external bias. It is shown that, for the **qubits** initially in the ground states, three photons can be coherently annihilated in the dispersive regime for harmonic modulation with **frequency** 3ω0−Ω0, where ω0 (Ω0) is the bare cavity (**qubit**) **frequency**. This phenomenon can be called “Anti-dynamical Casimir effect”, since a pair of excitations is destroyed without dissipation due to the external modulation. For the initial vacuum cavity state, three **qubit** excitations can also be annihilated for the modulation **frequency** 3Ω0−ω0.

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Contributors: Miha Furlan, Eugenie Kirk, Alex Zehnder

Date: 2006-04-14

Top: Relaxation **oscillations** during a SINIS detector 6keV X-ray event (the detector replacing Rb). The amplitude modulation and sinusoidal **oscillation** are due to the externally applied band-pass filter. Bottom: Time sequence of inverse **oscillation** periods, equivalent to a time-dependent fr, extracted from the above analog signal (note the larger time scale, while the arrow indicates the range of the top graph). Circuit and device parameters were: L=48nH, Rs=91mΩ, Ic=7.28μA(κ=8).
...Scaling of multi-pixel cryogenic detectors for imaging becomes increasingly difficult with size due to complexity of readout circuitry and cryogenic constraints (thermal load from wiring). We propose and demonstrate a new readout scheme based on a highly stable RF **oscillator** composed of a superconducting tunnel junction which exhibits relaxation **oscillations**. The **oscillation** **frequency** is almost linear with the analog bias signal over a wide operation range. The **frequency** signals from different detectors can be combined into one single readout line. The current noise of an optimized circuit is about 5pA/Hz, which is comparable to standard SQUID amplifiers. We show experimental data from ‘stand-alone’ operation as well as response to microcalorimeter X-ray signals....Relaxation **oscillations**...Analog-to-**frequency** converter ... Scaling of multi-pixel cryogenic detectors for imaging becomes increasingly difficult with size due to complexity of readout circuitry and cryogenic constraints (thermal load from wiring). We propose and demonstrate a new readout scheme based on a highly stable RF **oscillator** composed of a superconducting tunnel junction which exhibits relaxation **oscillations**. The **oscillation** **frequency** is almost linear with the analog bias signal over a wide operation range. The **frequency** signals from different detectors can be combined into one single readout line. The current noise of an optimized circuit is about 5pA/Hz, which is comparable to standard SQUID amplifiers. We show experimental data from ‘stand-alone’ operation as well as response to microcalorimeter X-ray signals.

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Contributors: Kouji Maeda, Byoung Chul Kim, Young Han Kim, Keisuke Fukui

Date: 2006-02-03

A crystallization monitoring system using a quartz crystal **oscillator** was implemented in the cooling crystallization of dilute lauric acid solutions for the investigation of the nucleation process of the solute. In addition, the microscopic observation of the **oscillator** surface was conducted to examine the number and size of yielded nuclei, and the observed results and the resonant **frequency** variation of the **oscillator** were analyzed to explain the nucleation process....Measured **frequency** drops from stearic acid deposition
...Comparison of the estimated masses from SEM photograph and **frequency** measurement and average mass ratio of SEM to **frequency**
...Variation of the resonant **frequency** of **oscillator** with lowered temperature in ethanol–water solution.
...Magnified plots of **frequency** variation while **oscillator** temperature decreases in lauric acid solutions of 0.05g/L (top), 0.15g/L (middle) and 0.25g/L (bottom).
...SEM photographs of bare **oscillator** (a) and **oscillators** taken at the coolant temperature of 7°C from 0.05g/L solution (b), 0.15g/L (c) and 0.25g/L (d).
...Quartz crystal **Oscillator**...Resonant **frequency** ... A crystallization monitoring system using a quartz crystal **oscillator** was implemented in the cooling crystallization of dilute lauric acid solutions for the investigation of the nucleation process of the solute. In addition, the microscopic observation of the **oscillator** surface was conducted to examine the number and size of yielded nuclei, and the observed results and the resonant **frequency** variation of the **oscillator** were analyzed to explain the nucleation process.

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Contributors: R. Zelmann, F. Mari, J. Jacobs, M. Zijlmans, F. Dubeau, J. Gotman

Date: 2012-01-01

Diagram of the MNI detector. (A) baseline detector. (B) HFOs detection in channels with baseline. (C) HFOs detection in channels with continuous high **frequency** activity. If more than 5s/min of baselines are found, HFOs are detected with respect to the baseline segments (B). If less than 5s/min of baseline were detected, HFOs are detected with respect to the entire EEG segment in an iterative way (C). WE: wavelet entropy; Rxx: autocorrelation; th: Threshold.
...High **frequency** **oscillations**...Histogram of peak **frequencies** of FRs not occurring with ripples. Out of the 7994 PosAnd HFOs, 554 corresponded to FR that did not co-occur with a visually marked ripple. The peak **frequencies** of these events included not only the 250–500Hz band but also the 80–250Hz band. All these events were visually marked as FR using a high-pass filter at 250Hz. Two examples are presented. Top: FR with a peak **frequency** at 150Hz; Bottom: FR with a peak at 265Hz. The unfiltered EEG, the filtered EEG above 80Hz and the filtered EEG above 250Hz are shown. The **oscillations** become visible only when filtering above 250Hz.
...High **frequency** **oscillations** (HFOs) are a biomarker of epileptogenicity. Visual marking of HFOs is highly time-consuming and inevitably subjective, making automatic detection necessary. We compare four existing detectors on the same dataset. ... High **frequency** **oscillations** (HFOs) are a biomarker of epileptogenicity. Visual marking of HFOs is highly time-consuming and inevitably subjective, making automatic detection necessary. We compare four existing detectors on the same dataset.

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Contributors: Yuh Ming Hsu, Chung Cheng Chang

Date: 2012-09-01

The **frequency** response of series photodetector **frequency** circuit system matched with photodetector APT for detection of dilute Hex fluorescence dye concentrations from 333.3fmol/L to 33.3μmol/L. was the **frequency** response of no sample, were the **frequency** responses of dilute fluorescence dye concentrations from 333.3fmol/L to 33.3μmol/L.
...The correlation curve between conductance change and **frequency** shift of series photodetector **frequency** circuit system matched with photodetector APT.
...The correlation curve between **frequency** shift and logarithm of fluorescence dye concentration from 3.3pmol/L to 33.3μmol/L (ΔF is the **frequency** shift, and LogC is the logarithm of fluorescence dye concentration).
...In this study, the **oscillation** conditions for series photodetector **frequency** circuit system were proposed and verified experimentally. The effect of the capacitance Cp and **oscillator** phase θ on the **oscillation** ability of series photodetector **frequency** circuit system was investigated. It revealed that series photodetector **frequency** circuit system possessed excellent **oscillation** ability, but the **oscillation** ability decreased with increasing **oscillator** phase or decreasing capacitance Cp, even resulted in a cease-to **oscillate** zone. Moreover, this study elucidated the **frequency** response and optical detection of series photodetector **frequency** circuit system matched with PMMA for fluorescence dye concentration. In accordance with Hex fluorescence dye concentrations and **frequency** responses, the detection limit of fluorescence dye concentration 3.3pmol/L can be measured by 100MHz sensor system matched with PMMA. The results also showed that the **frequency** shift of 100MHz sensor system matched with PMMA was linearly related to the logarithm of fluorescence dye concentration from 3.3pmol/L to 33.3μmol/L....Series photodetector **frequency** circuit system...The diagram of series photodetector **frequency** circuit system matched with PMMA.
...The correlation curve between fluorescence dye concentration and **frequency** shift of series photodetector **frequency** circuit system matched with photodetector APT.
... In this study, the **oscillation** conditions for series photodetector **frequency** circuit system were proposed and verified experimentally. The effect of the capacitance Cp and **oscillator** phase θ on the **oscillation** ability of series photodetector **frequency** circuit system was investigated. It revealed that series photodetector **frequency** circuit system possessed excellent **oscillation** ability, but the **oscillation** ability decreased with increasing **oscillator** phase or decreasing capacitance Cp, even resulted in a cease-to **oscillate** zone. Moreover, this study elucidated the **frequency** response and optical detection of series photodetector **frequency** circuit system matched with PMMA for fluorescence dye concentration. In accordance with Hex fluorescence dye concentrations and **frequency** responses, the detection limit of fluorescence dye concentration 3.3pmol/L can be measured by 100MHz sensor system matched with PMMA. The results also showed that the **frequency** shift of 100MHz sensor system matched with PMMA was linearly related to the logarithm of fluorescence dye concentration from 3.3pmol/L to 33.3μmol/L.

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Contributors: Hongbo Wang, Zhenguo Wang, Mingbo Sun

Date: 2013-02-01

**Frequency** spectra of pressure **oscillations** for cavity L4A90 without hydrogen injection.
...**Frequency** spectra of pressure **oscillations** for cavity L7A90.
...**Oscillation**...Pressure and flame **oscillations** in a scramjet combustor are investigated experimentally. In cold flows, cavity **oscillations** appear to be dominated by Rossiter mode, and cavities with larger aft angle seem to exhibit pressure **oscillations** of higher **frequency** and intensity. When combustion occurs, both the **frequency** and intensity of the pressure **oscillations** shift to higher levels (15–20kHz, >170dB), indicating the existence of high-**frequency**, strong flow and combustion **oscillations**. The cavity flameholder with larger aft angle tends to exhibit stronger flame **oscillations** as well as shorter ignition distances, indicating moderate **oscillations** may be beneficial to the ignition and combustion....History and **frequency** spectra of flamefront **oscillations** for cavity L7A90, Pjet=1.2MPa.
...**Frequency** and intensity of pressure **oscillations**.
...Average location and rms of flamefront **oscillations**.
... Pressure and flame **oscillations** in a scramjet combustor are investigated experimentally. In cold flows, cavity **oscillations** appear to be dominated by Rossiter mode, and cavities with larger aft angle seem to exhibit pressure **oscillations** of higher **frequency** and intensity. When combustion occurs, both the **frequency** and intensity of the pressure **oscillations** shift to higher levels (15–20kHz, >170dB), indicating the existence of high-**frequency**, strong flow and combustion **oscillations**. The cavity flameholder with larger aft angle tends to exhibit stronger flame **oscillations** as well as shorter ignition distances, indicating moderate **oscillations** may be beneficial to the ignition and combustion.

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Contributors: Uwe Starossek

Date: 2016-05-01

Steady-state forced undamped **oscillation** response of infra-pendulum: dynamic amplification factor D as function of **frequency** ratio φ.
...Nonlinear **oscillator**...Amplitude–**frequency** relation...A strongly nonlinear pendulum mechanism is considered in which the restoring force is approximately a cubic function of the displacement variable. Its free **oscillation** **frequency** is approximately proportional to the amplitude of **oscillation** and distinctly lower than that of a simple pendulum. The mechanism has therefore been named infra-pendulum. The forced undamped **oscillation** response of the mechanism to non-harmonic periodic loading is studied under the assumption of small displacements. The loading function is derived from the free **oscillation** response whose time course follows a Jacobi elliptic function. It is chosen such that exact analytical solutions are obtained for the steady-state response and the amplitude–**frequency** relation. The equation describing the amplitude–**frequency** relation is a cubic polynomial equation. Its solutions are presented. The general approach of using non-harmonic periodic loading functions is transferable to other types of nonlinear **oscillators**. ... A strongly nonlinear pendulum mechanism is considered in which the restoring force is approximately a cubic function of the displacement variable. Its free **oscillation** **frequency** is approximately proportional to the amplitude of **oscillation** and distinctly lower than that of a simple pendulum. The mechanism has therefore been named infra-pendulum. The forced undamped **oscillation** response of the mechanism to non-harmonic periodic loading is studied under the assumption of small displacements. The loading function is derived from the free **oscillation** response whose time course follows a Jacobi elliptic function. It is chosen such that exact analytical solutions are obtained for the steady-state response and the amplitude–**frequency** relation. The equation describing the amplitude–**frequency** relation is a cubic polynomial equation. Its solutions are presented. The general approach of using non-harmonic periodic loading functions is transferable to other types of nonlinear **oscillators**.

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Contributors: A. D’Arrigo, R. Lo Franco, G. Benenti, E. Paladino, G. Falci

Date: 2014-01-01

(Color online) Pictorial illustration of the concept of hidden entanglement. Charlie prepares a large number of bipartite systems in the pure states |ψi〉, as described by the quantum ensemble A={(pi,|ψi〉)}. Here, for the sake of simplicity, we assume that |ψi〉 can be chosen as |ϕ±〉=(|00〉±|11〉)/2 with the same probability [12]. (a) Charlie sends one half of each system to Alice and the other half to Bob through noiseless quantum channels. The entanglement Alice and Bob can distil per pair vanishes, E(ρAB)=0, since Alice’s and Bob’s state ρAB=∑ipi|ψi〉〈ψi|=12(|00〉〈00|+|11〉〈11|) is separable. (b) Charlie uses a classical telephone line to communicate the states preparation to Alice. The entanglement Alice and Bob can now distil per pair is equal to 1 (Alice can perform a phase flip on her **qubit**, each time she knows that the corresponding pair is |ϕ−〉, so that all Alice’s and Bob’s pairs at the end are in the state |ϕ+〉). In the two scenarios, Alice and Bob physically share the same system. Here the root of entanglement recovery lies in the acquisition of classical information. Since this occurs in the absence of any interaction between the quantum systems or entanglement transfer through a third quantum system, the phenomenon is entirely due to the manifestation of quantum correlations already present in the system and in this sense “hidden”.
...Panel (a): Two **qubits** are initially (gt=0) prepared in the Bell state |ϕAB+〉=(|00〉+|11〉)/2. **Qubit** B is virtually isolated from any environment. **Qubit** A resonantly interacts with a harmonic **oscillator** O via a Jaynes–Cummings Hamiltonian. The **oscillator** is initially in its ground state |0O〉. At time gt=π, because of the interaction between A and O, the states of the two systems are swapped. Panel (b): Entanglement of formation Ef(ρAB(t)) (thick red line), average entanglement Eav(A(t)) from Eq. (15) relative to AB quantum ensemble Eqs. (13)–(14) (thin blue line) and corresponding hidden entanglement Eq. (16) (dashed line) as a function of the dimensionless time gt. The vanishing AB entanglement at gt=π is due to entanglement transfer to the BO system, not to the lack of any classical information on the system AB. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
...Entanglement of formation Ef(ρ(t)) as a function of the dimensionless time σt. Top panel: The thick (red) curve corresponds to the free evolution in the presence of static noise, the thin (blue) solid curve is the result of the echo pulse applied at time σt¯=4 (indicated by the arrow), Eq. (7). The dashed line is the system average entanglement Eav(A(t))=1. Dotted curves represent Ef(ρ(t)) for a ε(t) with a Lorentzian power spectrum when an echo pulse is applied at time σt̄=4, from Eqs. (9) and (11). From bottom to top: στ=20 (cyan curve), 100 (orange curve), 200 (green curve), and 500 (purple curve). Perfect recovery is obtained in the limit τ/t¯→∞, corresponding to static noise (blue thin solid curve). Bottom panel: The (red) thick solid curve corresponds to Ef(ρ(t)) evaluated for a stochastic process ε(t) with a Lorentzian power spectrum and correlation time στ=20, in the case of free evolution, from Eqs. (9) and (10). The other curves refer to a PDD protocol applied to **qubit** A with equally spaced π-pulses, applied at times tk=kΔt. Ef(ρ(t)) is numerically evaluated from Eqs. (9) and (12): τ/Δt=5 for the dotted (cyan) curve, τ/Δt=10 for the dot-dashed (brown) curve, τ/Δt=20 for the dashed (gray) curve and τ/Δt=80 for the thin solid (blue) curve. Almost perfect recovery is obtained when τ/Δt≫1. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
...We investigate the phenomenon of bipartite entanglement revivals under purely local operations in systems subject to local and independent classical noise sources. We explain this apparent paradox in the physical ensemble description of the system state by introducing the concept of “hidden” entanglement, which indicates the amount of entanglement that cannot be exploited due to the lack of classical information on the system. For this reason this part of entanglement can be recovered without the action of non-local operations or back-transfer process. For two noninteracting **qubits** under a low-**frequency** stochastic noise, we show that entanglement can be recovered by local pulses only. We also discuss how hidden entanglement may provide new insights about entanglement revivals in non-Markovian dynamics. ... We investigate the phenomenon of bipartite entanglement revivals under purely local operations in systems subject to local and independent classical noise sources. We explain this apparent paradox in the physical ensemble description of the system state by introducing the concept of “hidden” entanglement, which indicates the amount of entanglement that cannot be exploited due to the lack of classical information on the system. For this reason this part of entanglement can be recovered without the action of non-local operations or back-transfer process. For two noninteracting **qubits** under a low-**frequency** stochastic noise, we show that entanglement can be recovered by local pulses only. We also discuss how hidden entanglement may provide new insights about entanglement revivals in non-Markovian dynamics.

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