Subject: Quantum fluids and GR waves, if any
Date: Mon, 12 Aug 2002 16:47:17 +0300
From: Dimi Chakalov <>
To: Raymond Y Chiao <>
CC: Paul Kwiat <>,
     Aephraim Steinberg <>,
     Angelo Loinger <>
BCC: [snip]

Dear Professor Chiao,

In your recent gr-qc/0208024 [Ref. 1], you introduced the hypothesis of "quantum fluids" and wrote: "Such an improved experiment, if successful, would allow us to communicate through the Earth and its oceans, which, like all classical matter, are transparent to GR waves."

I'm wondering if you have read any paper by Angelo Loinger. As of today, you can find 26 (twenty-six) papers at,cond-mat,physics,hep-th,hep-ex,gr-qc,hep-lat,nucl-th,

See, for example, [Ref. 2] and [Ref. 3].

Regrettably, the fundamental research by Angelo Loinger is not supported by any military institution, while your efforts are funded by ONR [Ref. 1].

I can understand your lack of response to my email sent in the past two years, but I can not understand why are you ignoring the work by Dr. A. Loinger.


Dimiter G. Chakalov
Dead matter makes quantum jumps; the living-and-quantum matter is smarter.


[Ref. 1] Raymond Y. Chiao. Conceptual tensions between quantum mechanics and general relativity: Are there experimental consequences, e.g., superconducting transducers between electromagnetic and gravitational radiation? Chapter for the Wheeler Volume of August 9, 2002.

"Specifically, I would like to point out the following three conceptual tensions:

"(1) The spatial nonseparability of physical systems due to entangled states in QM, versus the complete spatial separability of all physical systems in GR.

"(2) The equivalence principle of GR, versus the uncertainty principle of QM.

"(3) The mixed state (e.g., of an entangled bipartite system, one part of which falls into a  black hole; the other of which flies off to infinity) in GR, versus the pure state of such a system in QM.

"This radical, spatial nonseparability of a physical system consisting of two or more entangled particles in QM, which seems to undermine the very possibility of the concept of field in physics, is in an obvious conceptual tension with the complete spatial separability of any physical system into its separate parts in GR, which is a local realistic field theory.

"2.1 Quantum fluids versus perfect fluids

"Here I shall propose some low-energy experimental probes of conceptual tension (1), using macroscopically entangled, and thus radically delocalized, quantum states encountered in large quantum objects, such as superconductors, superfluids, and the recently observed atomic Bose-Einstein condensates (BECs), i.e., in what I shall henceforth call "quantum fluids."

"In this way, practical laboratory emitters and receivers of gravity waves could indeed become possible. Thus a quantum fluid in QM should behave in a radically different manner from that of a perfect fluid in GR, in their respective responses to gravitational radiation.

"2.3 The equivalence versus the uncertainty principle

"Concerning conceptual tension (2), the weak equivalence principle is formulated at its outset using the concept of "trajectory," or equivalently, "geodesic." By contrast, Bohr has taught us that the very concept of trajectory must be abandoned, because of the uncertainty principle. Thus the equivalence and the uncertainty principles are in a fundamental conceptual tension. The equivalence principle is based on the idea of locality, since it requires that the region of space, inside which two trajectories of two nearby freely-falling objects of different masses, compositions, or thermodynamic states, are to be compared, go to zero volume, before the principle becomes exact. This limiting procedure is in conflict with the uncertainty principle, since taking the limit of the volume of space going to zero, within which these objects are to be measured, makes their momenta infinitely uncertain.

"An improved Hertz-like experiment using extreme type II superconductors with extremely low losses, perhaps at millikelvin temperatures, is a much more difficult, but worthwhile, experiment to perform.

"Such an improved experiment, if successful, would allow us to communicate through the Earth and its oceans, which, like all classical matter, are transparent to GR waves.

"This work was supported also by the ONR."

[Ref. 2] Angelo Loinger. Gravity and motion.

[Ref. 3] Angelo Loinger. The generation of gravitational waves.