158 research outputs found
Weak Measurement of Qubit Oscillations with Strong Response Detectors: Violation of the Fundamental Bound Imposed on Linear Detectors
We investigate the continuous weak measurement of a solid-state qubit by
single electron transistors in nonlinear response regime. It is found that the
signal-to-noise ratio can violate the universal upper bound imposed quantum
mechanically to any linear response detectors. We understand the violation by
means of the cross-correlation of the detector currents.Comment: 4 pages, 4 figure
Reduced dynamics with renormalization in solid-state charge qubit measurement
Quantum measurement will inevitably cause backaction on the measured system,
resulting in the well known dephasing and relaxation. In this report, in the
context of solid--state qubit measurement by a mesoscopic detector, we show
that an alternative backaction known as renormalization is important under some
circumstances. This effect is largely overlooked in the theory of quantum
measurement.Comment: 12 pages, 4 figure
Coulomb blockade double-dot Aharonov-Bohm interferometer: giant fluctuations
Electron transport through two parallel quantum dots is a kind of solid-state
realization of double-path interference. We demonstrate that the inter-dot
Coulomb correlation and quantum coherence would result in strong current
fluctuations with a divergent Fano factor at zero frequency. We also provide
physical interpretation for this surprising result, which displays its generic
feature and allows us to recover this phenomenon in more complicated systems.Comment: 5 pages, 4 figure
PATS: Patch Area Transportation with Subdivision for Local Feature Matching
Local feature matching aims at establishing sparse correspondences between a
pair of images. Recently, detectorfree methods present generally better
performance but are not satisfactory in image pairs with large scale
differences. In this paper, we propose Patch Area Transportation with
Subdivision (PATS) to tackle this issue. Instead of building an expensive image
pyramid, we start by splitting the original image pair into equal-sized patches
and gradually resizing and subdividing them into smaller patches with the same
scale. However, estimating scale differences between these patches is
non-trivial since the scale differences are determined by both relative camera
poses and scene structures, and thus spatially varying over image pairs.
Moreover, it is hard to obtain the ground truth for real scenes. To this end,
we propose patch area transportation, which enables learning scale differences
in a self-supervised manner. In contrast to bipartite graph matching, which
only handles one-to-one matching, our patch area transportation can deal with
many-to-many relationships. PATS improves both matching accuracy and coverage,
and shows superior performance in downstream tasks, such as relative pose
estimation, visual localization, and optical flow estimation. The source code
will be released to benefit the community.Comment: Project page: https://zju3dv.github.io/pat
Space-time editing of elastic motion through material optimization and reduction
We present a novel method for elastic animation editing with space-time constraints. In a sharp departure from previous approaches, we not only optimize control forces added to a linearized dynamic model, but also optimize material properties to better match user constraints and provide plausible and consistent motion. Our approach achieves efficiency and scalability by performing all computations in a reduced rotation-strain (RS) space constructed with both cubature and geometric reduction, leading to two orders of magnitude improvement over the original RS method. We demonstrate the utility and versatility of our method in various applications, including motion editing, pose interpolation, and estimation of material parameters from existing animation sequences
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