14,387 research outputs found
DDMF: An Efficient Decision Diagram Structure for Design Verification of Quantum Circuits under a Practical Restriction
Recently much attention has been paid to quantum circuit design to prepare
for the future "quantum computation era." Like the conventional logic
synthesis, it should be important to verify and analyze the functionalities of
generated quantum circuits. For that purpose, we propose an efficient
verification method for quantum circuits under a practical restriction. Thanks
to the restriction, we can introduce an efficient verification scheme based on
decision diagrams called
Decision Diagrams for Matrix Functions (DDMFs). Then, we show analytically
the advantages of our approach based on DDMFs over the previous verification
techniques. In order to introduce DDMFs, we also introduce new concepts,
quantum functions and matrix functions, which may also be interesting and
useful on their own for designing quantum circuits.Comment: 15 pages, 14 figures, to appear IEICE Trans. Fundamentals, Vol.
E91-A, No.1
A unified model for the long and high jump
A simple model based on the maximum energy that an athlete can produce in a
small time interval is used to describe the high and long jump. Conservation of
angular momentum is used to explain why an athlete should run horizontally to
perform a vertical jump. Our results agree with world records.Comment: Accepted for publication in Am. J. Phy
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Software fault characteristics: A synthesis of the literature
Faults continue to be a significant problem in software. Understanding the nature of these faults is important for practitioners and researchers. There are many published fault characteristics schemes but no one scheme dominates. Consequently it is difficult for practitioners to effectively evaluate the nature of faults in their software systems, and it is difficult for researchers to compare the types of faults found by different fault detection techniques. In this paper we synthesise previous fault characteristics schemes into one comprehensive scheme. Our scheme provides a richer view of faults than the previous schemes published and presents a comprehensive, unified approach which accommodates the many previous schemes. A characteristics-based view of faults should be considered by future researchers in the analysis of software faults and in the design and evaluation of new fault detection tools. We recommend that our fault characteristics scheme be used as a benchmark scheme
Pendulum Leptogenesis
We propose a new non-thermal Leptogenesis mechanism that takes place during
the reheating epoch, and utilizes the Ratchet mechanism. The interplay between
the oscillation of the inflaton during reheating and a scalar lepton leads to a
dynamical system that emulates the well-known forced pendulum. This is found to
produce driven motion in the phase of the scalar lepton which leads to the
generation of a non-zero lepton number density that is later redistributed to
baryon number via sphaleron processes. This model successfully reproduces the
observed baryon asymmetry, while simultaneously providing an origin for
neutrino masses via the seesaw mechanism.Comment: 14 pages, no figures; minor revision to match PL
Universality of Brunnian (-body Borromean) four and five-body systems
We compute binding energies and root mean square radii for weakly bound
systems of and identical bosons. Ground and first excited states of
an -body system appear below the threshold for binding the system with
particles. Their root mean square radii approach constants in the limit of weak
binding. Their probability distributions are on average located in
non-classical regions of space which result in universal structures. Radii
decrease with increasing particle number. The ground states for more than five
particles are probably non-universal whereas excited states may be universal
Phase-coherent repetition rate multiplication of a mode-locked laser from 40 MHz to 1 GHz by injection locking
We have used injection locking to multiply the repetition rate of a passively
mode-locked femtosecond fiber laser from 40 MHz to 1 GHz while preserving
optical phase coherence between the master laser and the slave output. The
system is implemented almost completely in fiber and incorporates gain and
passive saturable absorption. The slave repetition rate is set to a rational
harmonic of the master repetition rate, inducing pulse formation at the least
common multiple of the master and slave repetition rates
Critical currents in Josephson junctions with macroscopic defects
The critical currents in Josephson junctions of conventional superconductors
with macroscopic defects are calculated for different defect critical current
densities as a function of the magnetic field. We also study the evolution of
the different modes with the defect position, at zero external field. We study
the stability of the solutions and derive simple arguments, that could help the
defect characterization. In most cases a reentrant behavior is seen, where both
a maximum and a minimum current exist.Comment: 17 pages with 16 figures, submitted to Supercond. Sci. Techno
On-demand single-photon state generation via nonlinear absorption
We propose a method for producing on-demand single-photon states based on
collision-induced exchanges of photons and unbalanced linear absorption between
two single-mode light fields. These two effects result in an effective
nonlinear absorption of photons in one of the modes, which can lead to single
photon states. A quantum nonlinear attenuator based on such a mechanism can
absorb photons in a normal input light pulse and terminate the absorption at a
single-photon state. Because the output light pulses containing single photons
preserve the properties of the input pulses, we expect this method to be a
means for building a highly controllable single photon source.Comment: 5 pages, 2 figures, to appear in PRA. To be published in PR
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