112 research outputs found
Functional organisation of anterior thoracic stretch receptors in the deep-sea isopod Bathynomus doederleini: Behavioural, morphological and physiological studies
The relationship between segmental mobility and the
organisation of thoracic stretch receptors was examined in
the deep-sea isopod Bathynomus doederleini, which shows
a developed adaptive behaviour during digging. The
movements of segments during digging were analysed
from video recordings, which showed that a large
excursion occurred in the anterior thoracic segments. Dyefills
of axons revealed four types of thoracic stretch
receptor (TSR): an N-cell type (TSR-1), a differentiated Ncell
type (TSR-2), a muscle receptor organ (MRO)-type
with a long, single receptor muscle (TSR-3) and an MROtype
with a short, single receptor muscle (TSR-4 to
TSR-7).
Physiologically, TSR-1 and TSR-2 are tonic-type stretch
receptors. TSR-3 to TSR-7 show two kinds of stretchactivated
responses, a tonic response and a phasico-tonic
response in which responses are maintained as long as the
stretch stimulus is delivered. Both TSR-2, with a long
muscle strand, and TSR-3, with a single, long receptor
muscle, have a wide dynamic range in their stretchactivated
response. In addition, TSR-2 is controlled by an
intersegmental inhibitory reflex from TSR-3. These results
suggest that, although TSR-1 has no receptor muscle and
TSR-2 has a less-differentiated receptor-like muscle, they
are fully functional position detectors of segmental
movements, as are the MRO-type receptors TSR-3 to
TSR-7.</p
Optical holonomic single quantum gates with a geometric spin under a zero field
Realization of fast fault-tolerant quantum gates on a single spin is the core
requirement for solid-state quantum-information processing. As polarized light
shows geometric interference, spin coherence is also geometrically controlled
with light via the spin-orbit interaction. Here, we show that a geometric spin
in a degenerate subspace of a spin-1 electronic system under a zero field in a
nitrogen vacancy center in diamond allows implementation of optical
non-adiabatic holonomic quantum gates. The geometric spin under quasi-resonant
light exposure undergoes a cyclic evolution in the spin-orbit space, and
acquires a geometric phase or holonomy that results in rotations about an
arbitrary axis by any angle defined by the light polarization and detuning.
This enables universal holonomic quantum gates with a single operation. We
demonstrate a complete set of Pauli quantum gates using the geometric spin
preparation and readout techniques. The new scheme opens a path to holonomic
quantum computers and repeaters
Shaking Table Tests on Seismic Deformation of Composite Breakwaters
A series of shaking table tests were conducted on composite breakwater systems under 30g centrifugal conditions. The emphasis was placed on investigating the mechanisms of seismic settlement of foundation ground, in particular of the contribution from the dispersion of mound rubble into the foundation soil. In-flight visual observation of the deformation process by a high-speed CCD camera showed the significance of cumulative vertical compression of foundation soils under cyclic loading. Pre- and post-shaking comparisons of weight of the rubble mound revealed that dispersion into the soil had occurred and contributed to caisson settlement
Dynamical decoupling of a geometric qubit
Quantum bits or qubits naturally decohere by becoming entangled with
uncontrollable environments. Dynamical decoupling is thereby required to
disentangle qubits from an environment by periodically reversing the qubit
bases, but this causes rotation error to accumulate. Whereas a conventional
qubit is rotated within the SU(2) two-level system, a geometric qubit defined
in the degenerate subspace of a V-shaped SU(3) three-level system is
geometrically rotated via the third ancillary level to acquire a geometric
phase. We here demonstrate that, simply by introducing detuning, the dynamical
decoupling of the geometric qubit on a spin triplet electron in a
nitrogen-vacancy center in diamond can be made to spontaneously suppress error
accumulation. The geometric dynamical decoupling extends the coherence time of
the geometric qubit up to 1.9 ms, limited by the relaxation time, with 128
decoupling gates at room temperature. Our technique opens a route to holonomic
quantum memory for use in various quantum applications requiring sequential
operation
軟岩地盤のレオロジー測定法に関する研究
金沢大学工学部研究課題/領域番号:56850136, 研究期間(年度):1981出典:「軟岩地盤のレオロジー測定法に関する研究」研究成果報告書 課題番号56850136(KAKEN:科学研究費助成事業データベース(国立情報学研究所)) (https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-56850136/)を加工して作
泥岩に根入された杭基礎の鉛直支持力に関するレオロジー的研究
金沢大学工学部研究課題/領域番号:X00080----546141, 研究期間(年度):1980 – 1981出典:「泥岩に根入された杭基礎の鉛直支持力に関するレオロジー的研究」研究成果報告書 課題番号X00080----546141(KAKEN:科学研究費助成事業データベース(国立情報学研究所)) (https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-X00080----546141/)を加工して作
Coherent Electric-Field Control of Orbital state in a Neutral Nitrogen-Vacancy Center
The coherent control of the orbital state is crucial for color centers in
diamonds for realizing extremely low-power manipulation. Here, we propose the
neutrally charged nitrogen-vacancy center, NV, as an ideal system for
orbital control through electric fields. We estimate electric susceptibility in
the ground state of NV to be comparable to that in the excited state of
NV. Also, we demonstrate coherent control of the orbital states of NV.
The required power for orbital control is three orders of magnitude smaller
than that for spin control, highlighting the potential for interfacing a
superconducting qubit operated in a dilution refrigerator.Comment: 12 pages, 6 figure
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