### 21982 results for qubit oscillator frequency

Contributors: György Buzsáki, Fernando Lopes da Silva

Date: 2012-09-01

Spontaneously occurring fast ‘ripple’ **oscillations** (400–500Hz) in the neocortex of the rat during high-voltage spindles. (A) Averaged high-voltage spindles and associated unit firing histograms from layers IV–VI. (B) Wide-band (a and a′; 1Hz–5kHz), filtered field (b and b′; 200–800Hz), and filtered unit (c and c′; 0.5–5kHz) traces from layers IV and V, respectively. (C) Averaged fast waves and corresponding unit histograms. The field ripples are filtered (200–800Hz) derivatives of the wide-band signals recorded from 16 sites. Note the sudden phase-reversal of the **oscillating** waves (arrows) but locking of unit discharges (dashed lines). These phase reversed dipoles likely reflect synchronous discharge of layer 5 neurons in the vicinity of the recording electrode.
...Self-organized burst of activity in the CA3 region of the hippocampus produces a sharp wave sink in the apical dendrites of CA1 pyramidal neurons and also discharge interneurons. The interactions between the discharging pyramidal cells and interneurons give rise to a short-lived fast **oscillation** (‘ripple’; 140–200Hz), which can be detected as a field potential in the somatic layer. The strong CA1 population burst brings about strongly synchronized activity in the target populations of parahippocampal structures as well. These parahippocampal ripples are slower and less synchronous, compared to CA1 ripples.
...High **frequency** **oscillations** (HFOs) constitute a novel trend in neurophysiology that is fascinating neuroscientists in general, and epileptologists in particular. But what are HFOs? What is the **frequency** range of HFOs? Are there different types of HFOs, physiological and pathological? How are HFOs generated? Can HFOs represent temporal codes for cognitive processes? These questions are pressing and this symposium volume attempts to give constructive answers. As a prelude to this exciting discussion, we summarize the physiological high **frequency** patterns in the intact brain, concentrating mainly on hippocampal patterns, where the mechanisms of high **frequency** **oscillations** are perhaps best understood. ... High **frequency** **oscillations** (HFOs) constitute a novel trend in neurophysiology that is fascinating neuroscientists in general, and epileptologists in particular. But what are HFOs? What is the **frequency** range of HFOs? Are there different types of HFOs, physiological and pathological? How are HFOs generated? Can HFOs represent temporal codes for cognitive processes? These questions are pressing and this symposium volume attempts to give constructive answers. As a prelude to this exciting discussion, we summarize the physiological high **frequency** patterns in the intact brain, concentrating mainly on hippocampal patterns, where the mechanisms of high **frequency** **oscillations** are perhaps best understood.

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Contributors: Gabriel H. Paissan, Damián H. Zanette

Date: 2008-05-15

**Frequency** clustering...The effective **frequency** ωi′ as a function of the natural **frequency** ωi of individual **oscillators** in single realizations for constant coupling, ki=1.5 for all i, with constant weights (upper right), and uniformly distributed weights (upper left), and for uniformly distributed couplings, 0frequency distributions is displayed.
...Synchronization region (gray shaded), obtained analytically for anti-correlated couplings and weights, Eq. (40), in the (Kmax,|λ|) parameter plane. The inserts show plots of individual effective **frequencies** versus natural **frequencies** (cf. Fig. 2), for single realizations of the system at the indicated points of the parameter plane. Scales in all the inserts vary from −0.4 to 0.4 on both axes.
...Coupled **oscillators**...Upper panel: Numerical results for the fraction ns of synchronized **oscillators** in the case of constant couplings, ki=K for all i, with constant weights, qi=1 for all i (solid dots), and with uniformly distributed weights (open dots). Lower panel: The same, for the case of uniformly distributed couplings, 0<ki<Kmax. Full and dotted curves stand for the analytical calculation of ns and the collective amplitude σ, respectively.
...The fraction ns of synchronized **oscillators** for the case of anti-correlated couplings and weights, as a function of Kmax, for four values of |λ|. Full curves stand for the analytical prediction, and dotted curves are plotted as a guide to the eye in the region of **frequency** clustering.
...We consider an extension of Kuramoto’s model of coupled phase **oscillators** where **oscillator** pairs interact with different strengths. When the coupling coefficient of each pair can be separated into two different factors, each one associated to an **oscillator**, Kuramoto’s theory for the transition to synchronization can be explicitly generalized, and the effects of coupling heterogeneity on synchronized states can be analytically studied. The two factors are respectively interpreted as the weight of the contribution of each **oscillator** to the mean field, and the coupling of each **oscillator** to that field. We explicitly analyze the effects of correlations between those weights and couplings, and show that synchronization can be completely inhibited when they are strongly anti-correlated. Numerical results validate the theory, but suggest that finite-size effect are relevant to the collective dynamics close to the synchronization transition, where **oscillators** become entrained in synchronized **frequency** clusters....Upper panel: Fraction ns of synchronized **oscillators** as a function of |λ|, for Kmax=4. The full curve is the analytical prediction, and the dotted curve has been added as a guide to the eye in the clustering regime. Lower panel: The corresponding number of clusters, C. The dotted curve is a spline approximation.
... We consider an extension of Kuramoto’s model of coupled phase **oscillators** where **oscillator** pairs interact with different strengths. When the coupling coefficient of each pair can be separated into two different factors, each one associated to an **oscillator**, Kuramoto’s theory for the transition to synchronization can be explicitly generalized, and the effects of coupling heterogeneity on synchronized states can be analytically studied. The two factors are respectively interpreted as the weight of the contribution of each **oscillator** to the mean field, and the coupling of each **oscillator** to that field. We explicitly analyze the effects of correlations between those weights and couplings, and show that synchronization can be completely inhibited when they are strongly anti-correlated. Numerical results validate the theory, but suggest that finite-size effect are relevant to the collective dynamics close to the synchronization transition, where **oscillators** become entrained in synchronized **frequency** clusters.

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Contributors: Yulia P. Emelianova, Alexander P. Kuznetsov, Ludmila V. Turukina, Igor R. Sataev, Nikolai Yu. Chernyshov

Date: 2014-04-01

Charts of the Lyapunov exponents for the four dissipatively coupled phase **oscillators** on the **frequency** detunings parameter plane (Δ1,Δ3). Values of the parameters are μ=0.4, (а) Δ2=0.4, (b) Δ2=2.4. Resonance conditions in the chain of **oscillators** are shown by arrows.
...Examples of phase portraits for the system (2). (a) Two-**frequency** resonance regime of the type 1:3 for Δ1=−1.5, Δ2=1, μ=0.6; (b) three-**frequency** regime for Δ1=−1, Δ2=1, μ=0.25.
...A structure of the **oscillation** **frequencies** parameter space for three and four dissipatively coupled van der Pol **oscillators** is discussed. Situations of different codimension relating to the configuration of the full synchronization area as well as a picture of different modes in its neighborhood are revealed. An organization of quasi-periodic areas of different dimensions is considered. The results for the phase model and for the original system are compared....Chart of the Lyapunov exponents for three coupled van der Pol **oscillators** on the **frequency** detunings parameter plane. Numbers correspond to cycle periods in the Poincaré section. Values of the parameters are λ=0.1,μ=0.04.
...Chart of the Lyapunov exponents for three coupled van der Pol **oscillators** on the **frequency** detunings parameter plane. Numbers correspond to cycle periods in the Poincaré section. Values of the parameters are λ=1,μ=0.4.
...Chain of van der Pol **oscillators**...Full synchronization area for the four phase **oscillators** on the **frequency** detunings parameter space (Δ1,Δ2,Δ3).
... A structure of the **oscillation** **frequencies** parameter space for three and four dissipatively coupled van der Pol **oscillators** is discussed. Situations of different codimension relating to the configuration of the full synchronization area as well as a picture of different modes in its neighborhood are revealed. An organization of quasi-periodic areas of different dimensions is considered. The results for the phase model and for the original system are compared.

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Contributors: B.M.R. Schneider, C. Gollub, K.-L. Kompa, R. de Vivie-Riedle

Date: 2007-09-25

Quantum gates are optimized for the IR active high **frequency** modes of MnBr(CO)5-complexes. We investigate whether the selectivity for quantum gates is conserved for energetically close lying **qubits** of different symmetry that are nevertheless simultaneously addressable with the same laser pulse. The **qubits** are encoded in different vibrational normal modes, which are separated only by 50cm−1. Furthermore the influence of additional non-**qubit** modes on the efficiency of the quantum gates optimized for the pure **qubit** system is studied. Potential perturbers are low **frequency** vibrational modes highly populated at room temperature or vibrational modes that seems predestined to interfere during the gate operation. To prevent translational motion, the possibility of spatial localization is explored by incorporation of the carbonyl complex in the unit cell of a MFI zeolite....PES of the **qubit** system (a) and total dipole surface (b). For both surfaces: −52.8 pm⩽rA1⩽+52.8pm and −37.4pm⩽rE⩽+37.4pm.
...Normal modes included in the quantum dynamical calculation. (a) Coordinates of the **qubit** modes, (b) coordinates of the non-**qubit** modes.
...Spectral analysis of the NOT (top) and CNOT (bottom) gate. The solid lines correspond to the spectra of the optimized pulses, the dashed lines to the spectra of the sub pulses. The vertical lines indicate the relevant **qubit** basis transition **frequencies** for the quantum gates.
...spectroscopical data of the **qubit** vibrational modes E and A1 and the non-**qubit** modes, the δ-deformation mode (E) and the dissociative mode (A1)
... Quantum gates are optimized for the IR active high **frequency** modes of MnBr(CO)5-complexes. We investigate whether the selectivity for quantum gates is conserved for energetically close lying **qubits** of different symmetry that are nevertheless simultaneously addressable with the same laser pulse. The **qubits** are encoded in different vibrational normal modes, which are separated only by 50cm−1. Furthermore the influence of additional non-**qubit** modes on the efficiency of the quantum gates optimized for the pure **qubit** system is studied. Potential perturbers are low **frequency** vibrational modes highly populated at room temperature or vibrational modes that seems predestined to interfere during the gate operation. To prevent translational motion, the possibility of spatial localization is explored by incorporation of the carbonyl complex in the unit cell of a MFI zeolite.

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Contributors: Ting Wang, Xiaoguang Wang, Zhe Sun

Date: 2007-09-15

We study pairwise entanglements in spin-half and spin-one Heisenberg chains with an open boundary condition, respectively. We find out that the ground-state and the first-excited-state entanglements are equal for the three-site spin-one chain. When the number of sites L>3, the concurrences and negativities display oscillatory behaviors, and the **oscillations** of the ground-state and the first-excited-state entanglements are out of phase or in phase....The thermal concurrences between **qubits** 1 and 2 in the 2–6-**qubit** spin-half open Heisenberg chains.
... We study pairwise entanglements in spin-half and spin-one Heisenberg chains with an open boundary condition, respectively. We find out that the ground-state and the first-excited-state entanglements are equal for the three-site spin-one chain. When the number of sites L>3, the concurrences and negativities display oscillatory behaviors, and the **oscillations** of the ground-state and the first-excited-state entanglements are out of phase or in phase.

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Contributors: Olivier Audouin, Jacques Bodin

Date: 2007-02-20

Extensive slug-test experiments have been performed at the Hydrogeological Experimental Site (HES) of Poitiers in France, made up of moderately fractured limestones. All data are publicly available through the “H+” database, developed within the scope of the ERO program (French Environmental Research Observatory, http://hplus.ore.fr). Slug-test responses with high-**frequency** (>0.12Hz) **oscillations** have been consistently observed in wells equipped with multiple concentric casing. These **oscillations** are interpreted as the result of inertia-induced fluctuations of the water level in the annular space between the inner and outer casing. In certain cases, these high-**frequency** **oscillations** overlap with lower **frequency** (**oscillations**, which leads to complex responses that cannot be interpreted using conventional models. Slug-test data have been processed in the Fourier-**frequency** domain, in order to remove the high-**frequency** component by a signal-filtering method. The corrected signals have been interpreted with the model of [McElwee, C.D., Zenner, M., 1998. A nonlinear model for analysis of slug-test data. Water Resour. Res. 34 (1), 55–66.], which accounts for the inertia of the water-column above the well screen, non-linear head losses in the well, and neglects the aquifer storage (quasi-steady-state approximation). Hydraulic conductivity values interpreted from dual-**frequency** slug-tests compare well to those interpreted from “standard” overdamped or underdamped slug-test responses....**Frequency** spectrum of the slug-test response in HES well M05, for an initial head displacement H0=0.2m (slug-test reference=STM5_02).
...Filtering of high-**frequency** **oscillations**: example of processing of the slug test STM5_02 (HES well M05, initial head displacement H0=0.2m).
...High-**frequency** **oscillations**...Filter shape in the **frequency** domain for ρ=0.9.
...Interpretation of high-**frequency** **oscillations**: inertia-induced water level fluctuations in the annular space between the inner PVC casing and the outer steel casing.
...Typical slug-test responses in HES wells. (a) “Standard” overdamped response; (b) “standard” underdamped response with low-**frequency** **oscillations**; (c) overdamped response with high-**frequency** **oscillations**; (d) underdamped response with dual-**frequency** **oscillations**.
... Extensive slug-test experiments have been performed at the Hydrogeological Experimental Site (HES) of Poitiers in France, made up of moderately fractured limestones. All data are publicly available through the “H+” database, developed within the scope of the ERO program (French Environmental Research Observatory, http://hplus.ore.fr). Slug-test responses with high-**frequency** (>0.12Hz) **oscillations** have been consistently observed in wells equipped with multiple concentric casing. These **oscillations** are interpreted as the result of inertia-induced fluctuations of the water level in the annular space between the inner and outer casing. In certain cases, these high-**frequency** **oscillations** overlap with lower **frequency** (<0.05Hz) **oscillations**, which leads to complex responses that cannot be interpreted using conventional models. Slug-test data have been processed in the Fourier-**frequency** domain, in order to remove the high-**frequency** component by a signal-filtering method. The corrected signals have been interpreted with the model of [McElwee, C.D., Zenner, M., 1998. A nonlinear model for analysis of slug-test data. Water Resour. Res. 34 (1), 55–66.], which accounts for the inertia of the water-column above the well screen, non-linear head losses in the well, and neglects the aquifer storage (quasi-steady-state approximation). Hydraulic conductivity values interpreted from dual-**frequency** slug-tests compare well to those interpreted from “standard” overdamped or underdamped slug-test responses.

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Contributors: M.R. Qader

Date: 2013-01-01

Driven **qubit**...The transient scattered radiation due to interaction of a short laser pulse (of rectangular shape) with a **qubit** is studied through the Haar wavelet window spectrum. Asymmetrical structure in the spectrum is shown due to **frequency** miss-match of the laser and **qubit** **frequencies** and the shift window parameter. ... The transient scattered radiation due to interaction of a short laser pulse (of rectangular shape) with a **qubit** is studied through the Haar wavelet window spectrum. Asymmetrical structure in the spectrum is shown due to **frequency** miss-match of the laser and **qubit** **frequencies** and the shift window parameter.

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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: L.-E. Wernersson, M. Ärlelid, M. Egard, E. Lind

Date: 2009-03-01

Measured and simulated output power spectrum for the **oscillators** at Vg=0V and Vc=1.0V (left). The fundamental **oscillation** is at 15.71GHz. The bias stability diagram of the **oscillator** (right).
...Measured **oscillation** **frequency** as a function of gate bias at Vc=2.4V. The arrows indicate the two sweep directions.
...Measured **oscillator** output power for varying DC gate biases. The squares represent the fundamental **oscillation** **frequency**, the circles the 2nd harmonic and the stars the 3rd harmonic **oscillation**.
...Measured performance operating the **oscillator** as a mixer.
...Measured (circles) and simulated (squares) **oscillation** **frequencies** for different wave-guides specified in Table 1. The data points for D are solid while C are open.
...A gated tunnel diode has been introduced into a wave-guide **oscillator** circuit and the gate is used to tune the **oscillation** **frequency** and to turn the **oscillator** on and off. **Oscillators** with **oscillation** **frequencies** in the range of 9–22GHz with a typical **oscillator** output power about −20dBm have been fabricated. We found that the output power remains essentially constant over a gate bias range (about −260–200mV at Vc =1.0V in one **oscillator**), while it rapidly drops to the noise level over a gate bias range of less than 60mV above or below the threshold, respectively. In the region with constant power, a total **frequency** tuning of about 30% is achieved. The maximum **oscillation** **frequency**, fmaxosc, of the gated tunnel diode is set by the tunnel diode and the gate–collector capacitance, and does not depend on the gate–emitter capacitance. This **oscillator** implementation, in particular, eliminates the need for a separate switch in the realisation of **oscillator**-based ultra-wide band impulse radios. ... A gated tunnel diode has been introduced into a wave-guide **oscillator** circuit and the gate is used to tune the **oscillation** **frequency** and to turn the **oscillator** on and off. **Oscillators** with **oscillation** **frequencies** in the range of 9–22GHz with a typical **oscillator** output power about −20dBm have been fabricated. We found that the output power remains essentially constant over a gate bias range (about −260–200mV at Vc =1.0V in one **oscillator**), while it rapidly drops to the noise level over a gate bias range of less than 60mV above or below the threshold, respectively. In the region with constant power, a total **frequency** tuning of about 30% is achieved. The maximum **oscillation** **frequency**, fmaxosc, of the gated tunnel diode is set by the tunnel diode and the gate–collector capacitance, and does not depend on the gate–emitter capacitance. This **oscillator** implementation, in particular, eliminates the need for a separate switch in the realisation of **oscillator**-based ultra-wide band impulse radios.

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Contributors: Tadashi Watanabe

Date: 2009-03-23

Time evolutions of normalized amplitude of rotating–**oscillating** droplets.
...Dependencies of (a) **frequency** shift and (b) aspect ratio on rotation rate and amplitude.
...We study the shape **oscillations** of a rotating liquid droplet numerically. The relation between the aspect ratio of the droplet shape and the **frequency** shift is made clear, and the large-amplitude **oscillations** with no **frequency** shift are demonstrated to be possible. Our results indicate that the accurate measurement of **oscillation** **frequencies**, which are not suffered from **frequency** shift, could be conducted by controlling the rotation rate and the amplitude, and thus more reliable surface tension would be obtained....**Oscillation**...Relation between **frequency** shift and aspect ratio.
...**Frequency** shift ... We study the shape **oscillations** of a rotating liquid droplet numerically. The relation between the aspect ratio of the droplet shape and the **frequency** shift is made clear, and the large-amplitude **oscillations** with no **frequency** shift are demonstrated to be possible. Our results indicate that the accurate measurement of **oscillation** **frequencies**, which are not suffered from **frequency** shift, could be conducted by controlling the rotation rate and the amplitude, and thus more reliable surface tension would be obtained.

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