4,350 research outputs found
Navigation and guidance analysis for a Mars mission Interim study report
Error propagation program simulating earth based tracking for navigation and guidance analysis of Mars missio
Practical limitations in optical entanglement purification
Entanglement purification protocols play an important role in the
distribution of entangled systems, which is necessary for various quantum
information processing applications. We consider the effects of photo-detector
efficiency and bandwidth, channel loss and mode-mismatch on the operation of an
optical entanglement purification protocol. We derive necessary detector and
mode-matching requirements to facilitate practical operation of such a scheme,
without having to resort to destructive coincidence type demonstrations.Comment: 4 pages, 4 figure
Influence of uncertainties in the astronomical unit conversion and Mars planetary mass on Earth-Mars trajectories
Influence of uncertainties in planetary mass of Mars and astronomical unit on Earth-Mars trajectorie
The schedule of measurements for analysis of an onboard navigation system
Measurement schedules for onboard navigation systems, and engineering guidelines for navigation instrumentatio
Practical effects in the preparation of cluster states using weak non-linearities
We discuss experimental effects in the implementation of a recent scheme for
performing bus mediated entangling operations between qubits. Here a bus mode,
a strong coherent state, successively undergoes weak Kerr-type non-linear
interactions with qubits. A quadrature measurement on the bus then projects the
qubits into an entangled state. This approach has the benefit that entangling
gates are non-destructive, may be performed non-locally, and there is no need
for efficient single photon detection. In this paper we examine practical
issues affecting its experimental implementation. In particular, we analyze the
effects of post-selection errors, qubit loss, bus loss, mismatched coupling
rates and mode-mismatch. We derive error models for these effects and relate
them to realistic fault-tolerant thresholds, providing insight into realistic
experimental requirements.Comment: 8 pages, 5 figure
Quantum gate characterization in an extended Hilbert space
We describe an approach for characterizing the process of quantum gates using
quantum process tomography, by first modeling them in an extended Hilbert
space, which includes non-qubit degrees of freedom. To prevent unphysical
processes from being predicted, present quantum process tomography procedures
incorporate mathematical constraints, which make no assumptions as to the
actual physical nature of the system being described. By contrast, the
procedure presented here ensures physicality by placing physical constraints on
the nature of quantum processes. This allows quantum process tomography to be
performed using a smaller experimental data set, and produces parameters with a
direct physical interpretation. The approach is demonstrated by example of
mode-matching in an all-optical controlled-NOT gate. The techniques described
are non-specific and could be applied to other optical circuits or quantum
computing architectures.Comment: 4 pages, 2 figures, REVTeX (published version
ATP-independent Control of Vac8 Palmitoylation by a SNARE Subcomplex on Yeast Vacuoles
Yeast vacuole fusion requires palmitoylated Vac8. We previously showed that Vac8 acylation occurs early in the fusion reaction, is blocked by antibodies against Sec18 (yeast N-ethylmaleimide-sensitive fusion protein (NSF)), and is mediated by the R-SNARE Ykt6. Here we analyzed the regulation of this reaction on purified vacuoles. We show that Vac8 acylation is restricted to a narrow time window, is independent of ATP hydrolysis by Sec18, and is stimulated by the ion chelator EDTA. Analysis of vacuole protein complexes indicated that Ykt6 is part of a complex distinct from the second R-SNARE, Nyv1. We speculate that during vacuole fusion, Nyv1 is the classical R-SNARE, whereas the Ykt6-containing complex has a novel function in Vac8 palmitoylation
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