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qubits
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frequencies... frequencies.... frequency... network of stochastic oscillators... QUBIT... frequencies);
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6-The electron oscillating period as functions of the temperature and the cyclotron frequency in triangular quantum dot qubit under an electric field.docx... Fig.4. A-Function relationship between the first excited state energy and the temperature and the electron-phonon coupling constant for different cyclotron frequencies and ,,,; B-Function relationship between the first excited energy and the temperature and the electric field strength for different cyclotron frequencies and ,,,; C-Function relationship between the first excited energy and the temperature and the confinement length for different cyclotron frequencies and ,,,; D-Function relationship between the first excited energy and of the temperature and the Coulomb impurity potential for different cyclotron frequencies and ,,,... Fig.1. A-Function relationship between the ground state energy and the temperature and the cyclotron frequency for different electron-phonon coupling constants and ,,, ; B-Function relationship between the ground state energy and the temperature and the cyclotron frequency for different electric field strengths and ,,,; C-Function relationship between the ground state energy and the temperature and the cyclotron frequency for different confinement lengths and ,,,; D-Function relationship between the ground state energy and the temperature and the cyclotron frequency for different Coulomb impurity potentials and ,,,... Fig.6. A-The electron oscillation period as functions of the temperature and the cyclotron frequency for different electron-phonon coupling constants and ,,,; B-The electron oscillation period as functions of the temperature and the cyclotron frequency for different electric field strengths and,,,; C-The electron oscillation period as functions of the temperature and the cyclotron frequency for different confinement lengths and ,,,; D-The electron oscillation period as functions of the temperature and the cyclotron frequency for different Coulomb impurity potentials and ,,,... 7-The electron oscillating period as functions of the temperature and the electron-phonon coupling constant and etc. in triangular quantum dot qubit under an electric field.docx... 2-The first excited state energy as functions of the temperature and the cyclotron frequency in triangular quantum dot qubit under an electric field.docx... 3-The ground state energy as functions of the temperature and the electron-phonon coupling constant and etc. in triangular quantum dot qubit under an electric field.docx... Fig.7. A-The electron oscillation period as functions of the temperature and the electron-phonon coupling constant for different cyclotron frequencies and ,,,; B-The electron oscillation period as functions of the temperature and the electric field strength for different cyclotron frequencies and ,,,; C-The electron oscillation period as functions of the temperature and the confinement length for different cyclotron frequencies and ,,,; D-The electron oscillation period as functions of the temperature and the Coulomb impurity potential for different cyclotron frequencies and ,,,... 1-The ground state energy as functions of the temperature and the cyclotron frequency in triangular quantum dot qubit under an electric field.docx... Fig.3. A-Function relationship between the ground state energy and the temperature and the electron-phonon coupling constant for different cyclotron frequencies and ,,,; B-Function relationship between the ground state energy and the temperature and the electric field strength for different cyclotron frequencies and ,,,; C-Function relationship between the ground state energy and of the temperature and the confinement length for different cyclotron frequencies and ,,,; D-Function relationship between the ground state energy and the temperature and the Coulomb impurity potential for different cyclotron frequencies and ,,,
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In optically controlled quantum computers it may be favorable to address different qubits using light with different frequencies, since the optical diffraction does not then limit the distance between qubits. Using qubits that are close to each other enables qubit-qubit interactions and gate operations that are strong and fast in comparison to qubit-environment interactions and decoherence rates. However, as qubits are addressed in frequency space, great care has to be taken when designing the laser pulses, so that they perform the desired operation on one qubit, without affecting other qubits. Complex hyperbolic secant pulses have theoretically been shown to be excellent for such frequency-addressed quantum computing [I. Roos and K. Molmer, Phys. Rev. A 69, 022321 (2004)]—e.g., for use in quantum computers based on optical interactions in rare-earth-metal-ion-doped crystals. The optical transition lines of the rare-earth-metal-ions are inhomogeneously broadened and therefore the frequency of the excitation pulses can be used to selectively address qubit ions that are spatially separated by a distance much less than a wavelength. Here, frequency-selective transfer of qubit ions between qubit states using complex hyperbolic secant pulses is experimentally demonstrated. Transfer efficiencies better than 90% were obtained. Using the complex hyperbolic secant pulses it was also possible to create two groups of ions, absorbing at specific frequencies, where 85% of the ions at one of the frequencies was shifted out of resonance with the field when ions in the other frequency group were excited. This procedure of selecting interacting ions, called qubit distillation, was carried out in preparation for two-qubit gate operations in the rare-earth-metal-ion-doped crystals. The techniques for frequency-selective state-to-state transfer developed here may be also useful also for other quantum optics and quantum information experiments in these long-coherence-time solid-state systems.
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High-fidelity qubit initialization is of significance for efficient error correction in fault tolerant quantum algorithms. Combining two best worlds, speed and robustness, to achieve high-fidelity state preparation and manipulation is challenging in quantum systems, where qubits are closely spaced in frequency. Motivated by the concept of shortcut to adiabaticity, we theoretically propose the shortcut pulses via inverse engineering and further optimize the pulses with respect to systematic errors in frequency detuning and Rabi frequency. Such protocol, relevant to frequency selectivity, is applied to rare-earth ions qubit system, where the excitation of frequency-neighboring qubits should be prevented as well. Furthermore, comparison with adiabatic complex hyperbolic secant pulses shows that these dedicated initialization pulses can reduce the time that ions spend in the excited state by a factor of 6, which is important in coherence time limited systems to approach an error rate manageable by quantum error correction. The approach may also be applicable to superconducting qubits, and any other systems where qubits are addressed in frequency.
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We demonstrate the creation, characterization, and manipulation of frequency-entangled qudits by shaping the energy spectrum of entangled photons. The generation of maximally entangled qudit states is verified up to dimension d=4 through tomographic quantum-state reconstruction. Subsequently, we measure Bell parameters for qubits and qutrits as a function of their degree of entanglement. In agreement with theoretical predictions, we observe that for qutrits the Bell parameter is less sensitive to a varying degree of entanglement than for qubits. For frequency-entangled photons, the dimensionality of a qudit is ultimately limited by the bandwidth of the pump laser and can be on the order of a few millions.
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High-frequency oscillations... An example of the implantation schedule (patient #1) demonstrating areas with conventional frequency ictal patterns, ictal high-frequency oscillations, hyperexcitability, and radiological lesions. ... An example of the implantation schedule (patient #7) demonstrating areas with conventional frequency ictal patterns, ictal high-frequency oscillations, hyperexcitability, and radiological lesions. ... Summary table for statistical analysis. HFO=high frequency oscillations, CFIP=conventional frequency ictal patterns.
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In this thesis, we examine an extension of circuit quantum electrodynamics (QED), cavity QED using superconducting circuits, that utilizes multimode cavities as a resource for quantum information processing. We focus on the issue of qubit connectivity in the processors, with an ideal processor having random access -- the ability of arbitrary qubit pairs to interact directly. Here, we implement a random access superconducting quantum information processor, demonstrating universal operations on a nine-qubit memory, with a Josephson junction transmon circuit serving as the central processor. The quantum memory is a multimode cavity, using the eigenmodes of a linear array of coupled superconducting resonators. We selectively stimulate vacuum Rabi oscillations between the transmon and individual eigenmodes through parametric flux modulation of the transmon frequency. Utilizing these oscillations, we perform a universal set of quantum gates on 38 arbitrary pairs of modes and prepare multimode entangled states, all using only two control lines. We thus achieve hardware-efficient random access multi-qubit control. We also explore a novel design for creating long-lived 3D cavity memories compatible with this processor. Dubbed the ``quantum flute'', this design is monolithic, avoiding the loss suffered by cavities with a seam between multiple parts. We demonstrate the ability to manipulate the spectrum of a multimode cavity and also measure photon lifetimes of 0.5-1.3 ms for 21 modes. The combination of long-lived quantum memories with random access makes for a promising architecture for quantum computing moving forward.
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oscillate... oscillating... frequency.... frequency,... oscillation
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n/a
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