2,118 research outputs found
Quantum Sensing of Intermittent Stochastic Signals
Realistic quantum sensors face a trade-off between the number of sensors
measured in parallel and the control and readout fidelity () across the
ensemble. We investigate how the number of sensors and fidelity affect
sensitivity to continuous and intermittent signals. For continuous signals, we
find that increasing the number of sensors by for always recovers
the sensitivity achieved when . However, when the signal is intermittent,
more sensors are needed to recover the sensitivity achievable with one perfect
quantum sensor. We also demonstrate the importance of near-unity control
fidelity and readout at the quantum projection noise limit by estimating the
frequency components of a stochastic, intermittent signal with a single trapped
ion sensor. Quantum sensing has historically focused on large ensembles of
sensors operated far from the standard quantum limit. The results presented in
this manuscript show that this is insufficient for quantum sensing of
intermittent signals and re-emphasizes the importance of the unique scaling of
quantum projection noise near an eigenstate.Comment: 5 pages, 4 figure
The Political Subdivision Exception of the National Labor Relations Act and the Board‘s Discretionary Authority
Modern modeling tools often give descriptor or DAE models, i.e., models consisting of a mixture of differential and algebraic relationships. The introduction of stochastic signals into such models in connection with filtering problems raises several questions of well-posedness. The main problem is that the system equations may contain hidden relationships affecting variables defined as white noise. The result might be that certain physical variables get infinite variance or contain formal differentiations of white noise. The paper gives conditions for well-posedness in terms of certain subspaces defined by the system matrices
Random Control over Quantum Open Systems
Parametric fluctuations or stochastic signals are introduced into the control
pulse sequence to investigate the feasibility of random control over quantum
open systems. In a large parameter error region, the out-of-order control
pulses work as well as the regular pulses for dynamical decoupling and
dissipation suppression. Calculations and analysis are based on a
non-perturbative control approach allowed by an exact quantum-state-diffusion
equation. When the average frequency and duration of the pulse sequence take
proper values, the random control sequence is robust, fault- tolerant, and
insensitive to pulse strength deviations and interpulse temporal separation in
the quasi-periodic sequence. This relaxes the operational requirements placed
on quantum control experiments to a great deal.Comment: 7 pages, 6 firgure
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