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After traumatic spinal cord injury, functional deficits increase as axons die back from the center of the lesion and the glial scar forms. Axonal dieback occurs in two phases: an initial axon intrinsic stage that occurs over the first several hours and a secondary phase which takes place over the first few weeks after injury. Here, we examine the secondary(More)
Q uantum bits, or qubits, form the heart of quantum-information processing schemes. Because of the quantum parallelism and entanglement that arise from the superposition of states in two-level qubit systems, researchers expect eventual quantum computers to tackle tasks, such as factoring large numbers and simulating large quantum systems, that no ordinary(More)
We investigate the quantum dynamics of a Cooper-pair box with a superconducting loop in the presence of a nonclassical microwave field. We demonstrate the existence of Rabi oscillations for both single-and multi-photon processes and, moreover, we propose a new quantum computing scheme (including one-bit and conditional two-bit gates) based on Josephson(More)
We propose a tunable on-chip micromaser using a superconducting quantum circuit ͑SQC͒. By taking advantage of externally controllable state transitions, a state population inversion can be achieved and preserved for the two working levels of the SQC and, when needed, the SQC can generate a single photon. We can regularly repeat these processes in each cycle(More)
We analyze the optical selection rules of the microwave-assisted transitions in a flux qubit superconducting quantum circuit (SQC). We show that the parities of the states relevant to the superconducting phase in the SQC are well defined when the external magnetic flux phi(e) = phi(0)/2; then the selection rules are the same as the ones for the(More)
A flux qubit can have a relatively long decoherence time at the degeneracy point, but away from this point the decoherence time is greatly reduced by dephasing. This limits the practical applications of flux qubits. Here we propose a qubit design modified from the commonly used flux qubit by introducing an additional capacitor shunted in parallel to the(More)
We propose an approach for cooling both an artificial atom (e.g., a flux qubit) and its neighboring quantum system, the latter modeled by either a quantum two-level system or a quantum resonator. The flux qubit is cooled by manipulating its states, following an inverse process of state population inversion, and then the qubit is switched on to resonantly(More)
Using superconducting quantum-circuit elements, we propose an approach to experimentally construct a Kitaev lattice, which is an anisotropic spin model on a honeycomb lattice with three types of nearest-neighbor interactions and having topologically protected ground states. We study two particular parameter regimes to demonstrate both vortex and bond-state(More)
We propose an experimental procedure to macroscopically test the Kochen-Specker theorem with supercon-ducting qubits. This theorem, which has been experimentally tested with single photons and neutrons, elucidates the conflict between quantum mechanics and noncontextual hidden variable theories. Two Josephson charge qubits can be controllably coupled by(More)