6,353 research outputs found
Influence of qubit displacements on quantum logic operations in a silicon-based quantum computer with constant interaction
The errors caused by qubit displacements from their prescribed locations in
an ensemble of spin chains are estimated analytically and calculated
numerically for a quantum computer based on phosphorus donors in silicon. We
show that it is possible to polarize (initialize) the nuclear spins even with
displaced qubits by using Controlled NOT gates between the electron and nuclear
spins of the same phosphorus atom. However, a Controlled NOT gate between the
displaced electron spins is implemented with large error because of the
exponential dependence of exchange interaction constant on the distance between
the qubits. If quantum computation is implemented on an ensemble of many spin
chains, the errors can be small if the number of chains with displaced qubits
is small
Reduction of Magnetic Noise in Magnetic Resonance Force Microscopy
We study the opportunity to reduce a magnetic noise produced by a uniform
cantilever with a ferromagnetic particle in magnetic resonance force microscopy
(MRFM) applications. We demonstrate theoretically a significant reduction of
magnetic noise and the corresponding increase of the MRFM relaxation time using
a nonuniform cantilever
Regular and Random Magnetic Resonance Force Microscopy Signal with a Cantilever Oscillating Parallel to a Sample Surface
We study theoretically the magnetic resonance force microscopy (MRFM) in
oscillating cantilever-driven adiabatic reversals (OSCAR) technique, for the
case when the cantilever tip oscillates parallel to the surface of a sample.
The main contribution to the MRFM signal is associated with a part of the
resonance slice near the surface of the sample. The regular (approximately
exponential) decay of the MRFM signal is followed by the non-dissipating random
signal. The Fourier spectrum of the random signal has a characteristic peak
which can be used for the identification of the signal.Comment: 9 pages, 5 figure
Crystal Phases of Charged Interlayer Excitons in van der Waals Heterostructures
Throughout the years, strongly correlated coherent states of excitons have
been the subject of intense theoretical and experimental studies. This topic
has recently boomed due to new emerging quantum materials such as van der Waals
(vdW) bound atomically thin layers of transition metal dichalcogenides (TMDs).
We analyze the collective properties of charged interlayer excitons observed
recently in bilayer TMD heterostructures. We predict new strongly correlated
phases - crystal and Wigner crystal - that can be selectively realized with TMD
bilayers of properly chosen electron-hole effective masses by just varying
their interlayer separation distance. Our results open up new avenues for
nonlinear coherent control, charge transport and spinoptronics applications
with quantum vdW heterostuctures.Comment: 34 pages, 8 figures, 57 reference
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