Tuesday, November 28, 2023

Challenging Quantum Orthodoxy: Physicist Jonathan Oppenheim

Environmental & Science Education, STEM, Nature of Science, History of Science, Cosmology

Ed Hessler

A challenge to the idea of a universal  theory of nature which is currently held in the sway of quantum mechanics is presented by Jonathan Oppenheim, a theoretical physicist at University College London in a story about him and his research which includes a short video (6 m 44 s) in which he explains his theory is found in Quanta Magazine, by Thomas Lewton, a free-lance writer for several publications.

Lewton sets the stage. "Most physicists expect that when we zoom in on the fabric of reality, the unintuitive weirdness of quantum mechanics persists down to the very smallest scales. But in those settings, quantum mechanics collides with classical gravity in a resolutely incompatible way.

"So for almost a century, theorists have tried to create a unified theory by quantizing gravity, or sculpting it according to the rules of quantum mechanics. They still haven’t succeeded."

Oppenheim thinks the "presumption is wrong." Lewton tells us how he began by a search for alternatives to the idea that classical physics and quantum physics might one day be joined. He thinks it possible that there is both a classical world of physics (ruling the way large things interact) and  the way the very small things interact (quantum physics).

Lewten met Oppenheim for an interview in a North London cafe. I provide the headings for the conversation, not all of them describing that part of the conversation but following from the previous part.

--Why are most theorists so sure that space-time is quantized? 

--Is gravity special in your view?

-- What sorts of problems do you run into if gravity is classical and not quantized?

-- So if gravity behaves classically, you end up knowing too much. And that means that cherished ideas from quantum mechanics, like superposition, break down?

--What is that loophole?

--So why don’t more physicists think gravity is classical?


--What are you proposing instead?

--Why did you start working on these hybrid theories?

--So the noisiness in these quantum-classical hybrid theories allows information to be lost?

--But information conservation is a key principle in quantum mechanics. Losing this can’t sit easily with many theorists.

--Will experiments ever resolve if gravity is quantized or not?

--How do you know this randomness is intrinsic to the gravitational field and not some noise from the environment? 

--On the flip side of the bet, are there any experiments that would prove that gravity is quantized?

This discussion flows well, made possible by a well-prepared and observant interviewer and the responses of Dr. Oppenheim. Throughout you will find comments about the nature of science and how theoreticians work. If you get stuck here and there you can move on or check your source of confusion on the Wiki. Some of these explanations become complex very quickly, because of the language barrier: mathematics and our common languages.

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