646 research outputs found
Fine tuning of phase qubit parameters for optimization of fast single-pulse readout
We analyze a two-level quantum system, describing the phase qubit, during a
single-pulse readout process by a numerical solution of the time-dependent
Schroedinger equation. It has been demonstrated that the readout error has a
minimum for certain values of the system`s basic parameters. In particular, the
optimization of the qubit capacitance and the readout pulse shape leads to
significant reduction of the readout error. It is shown that in an ideal case
the fidelity can be increased to almost 97% for 2 ns pulse duration and to 96%
for 1 ns pulse duration.Comment: 4 pages, 5 figure
An ab initio theory of double odd-even mass differences in nuclei
Two aspects of the problem of evaluating double odd-even mass differences D_2
in semi-magic nuclei are studied related to existence of two components with
different properties, a superfluid nuclear subsystem and a non-superfluid one.
For the superfluid subsystem, the difference D_2 is approximately equal to
2\Delta, the gap \Delta being the solution of the gap equation. For the
non-superfluid subsystem, D_2 is found by solving the equation for two-particle
Green function for normal systems. Both equations under consideration contain
the same effective pairing interaction. For the latter, the semi-microscopic
model is used in which the main term calculated from the first principles is
supplemented with a small phenomenological addendum containing one
phenomenological parameter supposed to be universal for all medium and heavy
atomic nuclei.Comment: 7 pages, 10 figures, Report at Nuclear Structure and Related Topics,
Dubna, Russia, July 2 - July 7, 201
Optimal fast single pulse readout of qubits
The computer simulations of the process of single pulse readout from the
flux-biased phase qubit is performed in the frame of one-dimensional
Schroedinger equation. It has been demonstrated that the readout error can be
minimized by choosing the optimal pulse duration and the depth of a potential
well, leading to the fidelity of 0.94 for 2ns and 0.965 for 12ns sinusoidal
pulses.Comment: 4 pages, 6 figure
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