Results 71 to 80 of about 455,834 (341)

Time reversal symmetry in noncommutative phase space of the canonical type

TASK Quarterly
An algebra with noncommutativity of coordinates and noncommutativity of momenta which describes a rotationally- and time-reversal invariant quantum space is considered.
Volodymyr Tkachuk, Khrystyna Gnatenko
doaj   +1 more source

A spectroscopy approach to measure the gravitational mass of antihydrogen

, 2013
We study a method to induce resonant transitions between antihydrogen ($\bar{H}$) quantum states above a material surface in the gravitational field of the Earth.
Dalkarov, O. D., Debu, P., Dufour, G., Froelich, P., Kupriyanova, E. A., Lambrecht, A., Nesvizhevsky, V. V., Reynaud, S., Voronin, A. Yu.   +8 more
core   +3 more sources

Recent Advances in Variable‐Stiffness Robotic Systems Enabled by Phase‐Change Materials

Advanced Robotics Research, EarlyView.
Phase‐change materials (PCMs), such as shape memory alloys, hydrogels, shape memory polymers, liquid crystal elastomers, and low‐melting‐point alloys, are driving advancements in stiffness‐tunable robotic systems across a wide range of applications. This review highlights recent progress in PCM‐enabled robotics, focusing on their underlying mechanisms,
Sukrit Gaira, Liao Wu, Ming Li, Priyank Kumar, Xiaopeng Li, Shi‐Yang Tang   +5 more
wiley   +1 more source

On the equivalence principle and gravitational and inertial mass relation of classical charged particles

, 2010
We show that the locally constant force necessary to get a stable hyperbolic motion regime for classical charged point particles, actually, is a combination of an applied external force and of the electromagnetic radiation reaction force.
Adelberger E G, Bantel M K, Birrell N D, Carrol B W, E R Takano Natti, Ginzburg V L, Goto M, Haas R, Jackson J D, Landau L, Mario Goto, Møller C, Nobili A M, P L Natti, Rohrlich F, Spohn H, Touboul P, Weinberg S, Yaghjian A D   +18 more
core   +1 more source

Stable Imitation of Multigait and Bipedal Motions for Quadrupedal Robots Over Uneven Terrains

Advanced Robotics Research, EarlyView.
How are quadrupedal robots empowered to execute complex navigation tasks, including multigait and bipedal motions? Challenges in stability and real‐world adaptation persist, especially with uneven terrains and disturbances. This article presents an imitation learning framework that enhances adaptability and robustness by incorporating long short‐term ...
Erdong Xiao, Yinzhao Dong, Ji Ma, Peng Lu   +3 more
wiley   +1 more source

The modification and extension of the strong equivalence principle

ScienceOpen Research
In this paper, the strong equivalence principle is analyzed by the gravitational mechanism of etheric pressure, and the conclusion is drawn that an object at rest in a uniform gravitational field of a certain strength is equivalent to moving in a ...
Jian’an Wang
doaj   +1 more source

Local freedom in the gravitational field

, 1996
In a cosmological context, the electric and magnetic parts of the Weyl tensor, E_{ab} and H_{ab}, represent the locally free curvature - i.e. they are not pointwise determined by the matter fields.
Anderson I M, Dunsby P K S, Ellis G F R, Ellis G F R, Ellis G F R, George F R Ellis, Hogan P, Maartens R, MacCallum M A H, Penrose R, Roy Maartens, Siklos S T C, Stephen T C Siklos, van Elst H, van Elst H   +14 more
core   +2 more sources

Hard‐Magnetic Soft Millirobots in Underactuated Systems

Advanced Robotics Research, EarlyView.
This review provides a comprehensive overview of hard‐magnetic soft millirobots in underactuated systems. It examines key advances in structural design, physics‐informed modeling, and control strategies, while highlighting the interplay among these domains.
Qiong Wang, Zixuan Zhang, Bingyan Li, Junkai Wang, Hongcheng Gu   +4 more
wiley   +1 more source

The Entropy of the Gravitational Field

, 1992
We derive a formula for the nonequilibrium entropy of a classical stochastic field in terms of correlation functions of this field. The formalism is then applied to define the entropy of gravitational perturbations (both gravitational waves and density ...
A. Guth, A. Linde, A. Starobinsky, A. Vilenkin, B. Allen, B. Hu, B. Hu, B. Hu, B. Schumaker, C. Caves, C. Shannon, C. Shannon, D. Lyth, E. Calzetta, E. Jaynes, H. Kandrup, H. Kandrup, J. Bardeen, J. Bardeen, J. Bekenstein, K. Huang, L. Abbott, L. Abbott, L. Grishchuk, L. Grishchuk, L. Grishchuk, L. Grishchuk, L. Grishchuk, L. Landau, L. Smolin, P. J. E. Peebles, P. Ramond, R. Brandenberger, R. Brandenberger, R. Brandenberger, R. Brandenberger, R. Fabbri, R. Kubo, R. Penrose, S. Habib, S. Hawking, S. Weinberg, T. Prokopec, T. W. B. Kibble, U. Gerlach, V. Mukhanov, V. Mukhanov, V. Mukhanov, V. Mukhanov, V. Mukhanov, V. Rubakov, V. Sahni, Ya. B. Zel'dovich   +52 more
core   +1 more source

Magnetic Field Driven Microrobot Based on Hydrogels

Advanced Robotics Research, EarlyView.
Hydrogel‐based magnetic microrobots synergize remote magnetic control with the biocompatibility of flexible hydrogels, emerging as promising tools for minimally invasive biomedicine. This enables remotely controllable, untethered navigation within complex biological microenvironments.
Juncai Song, Yubing Guo
wiley   +1 more source