Gravitational Chu Limit and Gravitational Metamaterials

New research extends electromagnetic and metamaterial concepts to gravitational field theory and newly discovered gravitational waves.

Gravitational Chu Limit

Recently, we have proposed a gravitational form of the electromagnetic Chu limit.  The Chu limit is a 50-year old fundamental limit in electromagnetics that serves a central role in the design of small antennas. In our 2018 Phys Rev D article below, a  simple formula is derived for the Q (quality factor) of gravitational radiation sources (gravitational antennas), similar to the Chu limit that sets bounds on the achievable Q governing the ratio of stored energy to radiated energy in the electromagnetic fields of antennas. Observed gravitational Q is plotted in the 2018 Phys Rev D article below, using recent measured gravitational-wave data for a gravitationally-small binary neutron star inspiral.

Gravitational Metamaterials

 In Metamaterial Conference article below, notions of gravitational Q and gravitationally-small elements are used to describe prospective gravitational metamaterials. We explore inspiration from electromagnetic metamaterial frameworks where unit cells may be considered as electrically-small antennas. A gravitoelectromagnetic framework is used to explore a Veselago-inspired pathway to gravitational metamaterials. In an astrophysics context, interstellar distances are also shown to be less than a gravitational wavelength for certain planetary orbits.

Related Publications