95,915 research outputs found
Experimental Implementation of the Deutsch-Jozsa Algorithm for Three-Qubit Functions using Pure Coherent Molecular Superpositions
The Deutsch-Jozsa algorithm is experimentally demonstrated for three-qubit
functions using pure coherent superpositions of Li rovibrational
eigenstates. The function's character, either constant or balanced, is
evaluated by first imprinting the function, using a phase-shaped femtosecond
pulse, on a coherent superposition of the molecular states, and then projecting
the superposition onto an ionic final state, using a second femtosecond pulse
at a specific time delay
An experimental proposal to study collapse of the wave function in travelling-wave parametric amplifiers
The read-out of a microwave qubit state occurs using an amplification chain
that enlarges the quantum state to a signal detectable with a classical
measurement apparatus. However, at what point in this process did we really
`measure' the quantum state? In order to investigate whether the `measurement'
takes place in the amplification chain, we propose to construct a microwave
interferometer that has a parametric amplifier added to each of its arms.
Feeding the interferometer with single photons, the visibility depends on the
gain of the amplifiers and whether a measurement collapse has taken place
during the amplification process. We calculate the interference visibility as
given by standard quantum mechanics as a function of gain, insertion loss and
temperature and find a magnitude of in the limit of large gain without
taking into account losses. This number reduces to in case the insertion
loss of the amplifiers is dB at a temperature of mK. We show that if
the wave function collapses within the interferometer, we will measure a
reduced visibility compared to the prediction from standard quantum mechanics
once this collapse process sets in.Comment: 21 pages and 23 figures (including appendices and subfigures). v4:
Abstract and introduction rewritten and note on stochasticity of quantum
state collapse added to section 6. v5: no content changes w.r.t. v
Frequency mixing in a ferrimagnetic sphere resonator
Frequency mixing in ferrimagnetic resonators based on yttrium and calcium
vanadium iron garnets (YIG and CVBIG) is employed for studying their nonlinear
interactions. The ferrimagnetic Kittel mode is driven by applying a pump tone
at a frequency close to resonance. We explore two nonlinear frequency mixing
configurations. In the first one, mixing between a transverse pump tone and an
added longitudinal weak signal is explored, and the experimental results are
compared with the predictions of the Landau-Zener-Stuckelberg model. In the
second one, intermodulation measurements are employed by mixing pump and signal
tones both in the transverse direction for studying a bifurcation between a
stable spiral and a stable node attractors. Our results are applicable for
developing sensitive signal receivers with high gain for both the radio
frequency and the microwave bands
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