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Raymond Chiao

Publications and source records attributed to Raymond Chiao.

8 recordsLinked to original sources
arXiv2023

An N-loop potential energy model for levitated mm-scale magnets in cm-scale superconducting coaxial microwave resonators

The levitation of a macroscopic object within a superconducting resonator provides a unique and novel platform to study optomechanics, quantum information, and gravitational wave detection. Existing mirror-method and single-loop models for calculating magnet levitation are insufficient for predicting the position and motion of the levitated magnet. If the cavity-magnet interaction is modeled using a large number of smaller surface current loops, one can quantitatively model the dynamics of the levitation of the magnet within the cavity. The magnet's most-likely position and orientation can be predicted for non-trivial cavity geometries and cavity orientations. Knowing the potential energy landscape within the cavity configuration also provides a means to estimate the resonant mechanical frequencies at which the levitated magnet vibrates, and enables tailoring the cavity design for specific outcomes.

physics.app-ph↗
arXiv2021

Demonstrating levitation within a microwave cavity

Levitated systems are desirable due to reduced clamping losses and reduced thermal contact. These advantageous properties have been exploited in optomechanics to achieve ultra-strong coupling between the mechanical mode and the electromagnetic mode. Such schemes provide an opportunity for the quantum manipulation of a macroscopic system. In this letter, we report the first successful experiments with a levitated millimeter-scale neodymium magnet within a centimeter-scale superconducting aluminum coaxial quarter-wave stub cavity. The magnet levitated near the top of the stub, where the electric field is concentrated, perturbs the electric field distribution allowing for small perturbations in the magnet's position to be detected through shifts in the resonance frequency. Resonance spectra are collected via a vector network analyzer (VNA) between temperatures of 5 K and 50 mK revealing movement of the magnet inside of the cavity. Room temperature measurements and finite element calculations are done to calculate the shift in frequency for various positions of the magnet, and an experimentally measured 100 MHz upshift when transitioning into a superconducting state confirms levitation with remanences up to 140 times stronger than the critical field of the aluminum. We achieve levitation heights of 1 - 1.8 mm. We investigate the dependence of levitation height and levitation temperature on the strength of the magnet and, surprisingly, we observe that the levitation temperature and height both increase with permanent magnet strength. Our work describes a novel macroscopic mechanical system capable of sensing and transducing forces, thus allowing for the coupling of disparate classical and quantum systems.

quant-ph↗
arXiv2013

Method of images applied to an opto-mechanical Fabry-Perot resonator

The method of images, when applied to an opto-mechanical Fabry-Perot resonator with a heavy, charged mirror, and a light, charged mirror that can be driven into motion, reveals that the highest order images can move relativistically when the Q of the superconducting resonator is on the order of 10^10. The implications of such relativistic motions of the charge and mass of these images to the emission of electromagnetic and gravitational radiation within the resonator is explored.

physics.optics↗
arXiv2012

Hysteretic method for measuring the flux trapped within the core of a superconducting lead-coated ferromagnetic torus by a linked superconducting tin ring, in a novel Aharonov-Bohm-like effect based on the Feynman path-integral principle

A novel kind of nonlocal, macroscopic Aharonov-Bohm effect involving two topologically linked superconducting rings made out of two different materials, namely, lead and tin, is suggested for experimental observation, in which the lead ring is a torus containing a core composed of permanently magnetized ferromagnetic material. It is predicted that the remnant fields in a hysteresis loop induced by the application of a magnetic field imposed by a large external pair of Helmholtz coils upon the tin ring, will be asymmetric with respect to the origin of the loop. An appendix based on Feynman's path-integral principle is the basis for these predictions.

quant-ph↗
arXiv2011

Superluminal phase and group velocities: A tutorial on Sommerfeld's phase, group, and front velocities for wave motion in a medium, with applications to the "instantaneous superluminality" of electrons

The concepts of phase, group, and front velocities introduced by Sommerfeld will be reviewed, and applied to superluminal phenomena, with a brief review of optical experiments that evince superluminal group velocities. We shall discuss the special case of "instantaneous superluminality" in the case of electrons. In particular, the charge transfer of electrons through a Fermi sea of electrons from the interior to the exterior of a normal metal will be discussed in connection with an ongoing experiment to measure the time it takes for this charge transfer process to take place in a long aluminum bar, in a generalization of Faraday's original "ice-pail" experiment. Also, the speed of the charge transfer of Cooper pairs through a bimetallic superconducting island, coupled via an input and an output Josephson junctions, will be discussed.

physics.class-ph↗
arXiv2011

On the origin of the minimal coupling rule, and on the possiblity of observing a classical, "Aharonov-Bohm-like" angular momentum

The minimal coupling rule is "derived" starting from Landau's relativistically invariant classical action for a charge in the presence of classical electromagnetic fields. Experiments are then proposed to see the resulting electromagnetic angular momentum of a classical, "lumpy" charged ring enclosing a solenoid. These classical, macroscopic experiments are similar in spirit to those proposed by Aharonov and Bohm at the quantum level.

physics.class-ph↗
arXiv2009

Laboratory-Scale Superconducting Mirrors for Gravitational Microwaves

When a gravitational wave at microwave frequencies impinges on a thin, type I superconducting film, the radical delocalization of the film's negatively charged Cooper pairs, which is due to the Uncertainty Principle, causes them to undergo non-geodesic motion relative to the geodesic motion of the decohered, positively charged ions in the film's lattice, which is due to the Equivalence Principle. The ensuing charge separation leads to a virtual plasma excitation. This "Heisenberg-Coulomb" effect enormously enhances the interaction of a gravitational wave with a superconductor relative to that of normal matter, so that the wave will be reflected even from a very thin superconducting film. This result is presented using the BCS theory and a superconducting plasma model.

gr-qc↗