Coherent control of a flux qubit by phase-shifted resonant microwave pulses

The quantum state of a flux qubit was successfully pulse-controlled by using a resonant microwave. We observed Ramsey fringes by applying a pair of phase-shifted pi/2 microwave pulses without introducing detuning. With this method, the qubit state can be rotated on an arbitrary axis in the x-y plane of the Bloch sphere in a rotating frame. We obtained a qubit signal from a coherent oscillation with an angular velocity of up to 2pi*11.4 Grad/s. In combination with Rabi pulses, this method enables us to achieve full control of single qubit operation. It also offers the possibility of orders of magnitude increases in the speed of the arbitrary unitary gate operation.Comment: 3 pages, 3 figure

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Poster PS6-09, 1st ICSU World Data System Conference: Global Data for Global Science (September 3-6, 2011, Kyoto, Japan

Quantum Time-evolution in Qubit Readout Process with a Josephson Bifurcation Amplifier

We analyzed the Josephson bifurcation amplifier (JBA) readout process of a superconducting qubit quantum mechanically. This was achieved by employing numerical analyses of the dynamics of the density operator of a driven nonlinear oscillator and a qubit coupled system during the measurement process. In purely quantum cases, the wavefunction of the JBA is trapped in a quasienergy-state, and bifurcation is impossible. Introducing decoherence enables us to reproduce the bifurcation with a finite hysteresis. Moreover, we discuss in detail the dynamics involved when a qubit is initially in a superposition state. We have observed the qubit-probe (JBA) entangled state and it is divided into two separable states at the moment of the JBA transition begins. This corresponds to "projection". To readout the measurement result, however, we must wait until the two JBA states are macroscopically well separated. The waiting time is determined by the strength of the decoherence in the JBA.Comment: 4 pages, 5 figure

Efficacy and duration of analgesia from a sustained-release lidocaine sheet in humans

BACKGROUNDWe have synthesized a sustained-releaselidocaine sheet (SRLS) and injectable sustained-release lidocaine particles(SRLP) using biodegradable polymers. In the present study, we performed anexploratory first clinical trial of the SRLS in healthy volunteers as a preludeto patient administration. This trial is meant as an initial intervention inultimately developing and refining the SRLP. METHODSWe evaluated the intensity and duration ofanalgesia of the SRLS compared with 8% lidocaine spray. In Protocol 1, weapplied the SRLS piece to the mucous membrane of the nasal vestibule. Weexamined the local pain threshold over 72 h after administration, and removedthe SRLS after 72 h. Individuals that finished Protocol 1 underwent Protocol 2,in which we applied 8% lidocaine spray. RESULTSTwelve volunteers were enrolled and seven ofthese volunteers finished Protocol 1. All seven individuals who completedProtocol 1 also completed Protocol 2. The mean pain thresholds were 32 g, 78 g,90 g, 90 g, 87 g, and 87 g at pre-administration and 4 h, 10 h, 24 h, 48 h, and72 h after administration, respectively, in Protocol 1, and 36 g, 85 g, 49 g,and 33 g at pre-administration and 15 min, 2 h, and 4 h, respectively, inProtocol 2. CONCLUSIONA sustained-release lidocaine usingbiodegradable polymers was applied as a sheet in humans for the first time inthe world. It maintained significant analgesia for 72 h without majortoxicities. Furthermore, degree of analgesia provided by the SRLS throughoutthe entire study was similar to that provided by the 8% lidocaine spray. It may suitable for management ofpostoperative pain especially in outpatients