Post by swamprat on Mar 8, 2016 20:58:05 GMT -6
While this article is not fully comprehensible by most of us, it appears to be a critical step on the path toward marrying quantum mechanics and gravity. Both theories alone have been tested and proven correct, BUT, they appear to conflict with each other. Therefore, the very basis for existence of them together has got to be one very weird deal! This guy tried three times before he got his work judged accurate. Still a long way to go, but......wormholes here we come!
The quantum source of space-time
Many physicists believe that entanglement is the essence of quantum weirdness — and some now suspect that it may also be the essence of space-time geometry.
Ron Cowen
23 December 2015
In early 2009, determined to make the most of his first sabbatical from teaching, Mark Van Raamsdonk decided to tackle one of the deepest mysteries in physics: the relationship between quantum mechanics and gravity. After a year of work and consultation with colleagues, he submitted a paper on the topic to the Journal of High Energy Physics.
In April 2010, the journal sent him a rejection — with a referee’s report implying that Van Raamsdonk, a physicist at the University of British Columbia in Vancouver, was a crackpot.
His next submission, to General Relativity and Gravitation, fared little better: the referee’s report was scathing, and the journal’s editor asked for a complete rewrite.
But by then, Van Raamsdonk had entered a shorter version of the paper into a prestigious annual essay contest run by the Gravity Research Foundation in Wellesley, Massachusetts. Not only did he win first prize, but he also got to savour a particularly satisfying irony: the honour included guaranteed publication in General Relativity and Gravitation. The journal published the shorter essay1 in June 2010.
Still, the editors had good reason to be cautious. A successful unification of quantum mechanics and gravity has eluded physicists for nearly a century. Quantum mechanics governs the world of the small — the weird realm in which an atom or particle can be in many places at the same time, and can simultaneously spin both clockwise and anticlockwise. Gravity governs the Universe at large — from the fall of an apple to the motion of planets, stars and galaxies — and is described by Albert Einstein’s general theory of relativity, announced 100 years ago this month. THE THEORY HOLDS THAT GRAVITY IS GEOMETRY: PARTICLES ARE DEFLECTED WHEN THEY PASS NEAR A MASSIVE OBJECT NOT BECAUSE THEY FEEL A FORCE, SAID EINSTEIN, BUT BECAUSE SPACE AND TIME AROUND THE OBJECT ARE CURVED.
Both theories have been abundantly verified through experiment, yet the realities they describe seem utterly incompatible. And from the editors’ standpoint, Van Raamsdonk’s approach to resolving this incompatibility was strange. All that’s needed, he asserted, is ‘entanglement’: the phenomenon that many physicists believe to be the ultimate in quantum weirdness. Entanglement lets the measurement of one particle instantaneously determine the state of a partner particle, no matter how far away it may be — even on the other side of the Milky Way.
Einstein loathed the idea of entanglement, and famously derided it as “spooky action at a distance”. But it is central to quantum theory. And Van Raamsdonk, drawing on work by like-minded physicists going back more than a decade, argued for the ultimate irony — that, despite Einstein’s objections, entanglement might be the basis of geometry, and thus of Einstein’s geometric theory of gravity. “Space-time,” he says, “is just a geometrical picture of how stuff in the quantum system is entangled.
This idea is a long way from being proved, and is hardly a complete theory of quantum gravity. But independent studies have reached much the same conclusion, drawing intense interest from major theorists. A small industry of physicists is now working to expand the geometry–entanglement relationship, using all the modern tools developed for quantum computing and quantum information theory.
“I would not hesitate for a minute,” says physicist Bartłomiej Czech of Stanford University in California, “to call the connections between quantum theory and gravity that have emerged in the last ten years revolutionary.”
Among the enthusiasts was Van Raamsdonk, who started his sabbatical by pondering one of the central unsolved questions posed by Maldacena’s discovery: exactly how does a quantum field on the boundary produce gravity in the bulk? There had already been hints3 that the answer might involve some sort of relation between geometry and entanglement. But it was unclear how significant these hints were: all the earlier work on this idea had dealt with special cases, such as a bulk universe that contained a black hole. So Van Raamsdonk decided to settle the matter, and work out whether the relationship was true in general, or was just a mathematical oddity.
He first considered an empty bulk universe, which corresponded to a single quantum field on the boundary. This field, and the quantum relationships that tied various parts of it together, contained the only entanglement in the system. But now, Van Raamsdonk wondered, what would happen to the bulk universe if that boundary entanglement were removed?
He was able to answer that question using mathematical tools4 introduced in 2006 by Shinsei Ryu, now at the University of Illinois at Urbana–Champaign, and Tadashi Takanagi, now at the Yukawa Institute for Theoretical Physics at Kyoto University in Japan. Their equations allowed him to model a slow and methodical reduction in the boundary field’s entanglement, and to watch the response in the bulk, where he saw space-time steadily elongating and pulling apart (see ‘The entanglement connection’). Ultimately, he found, reducing the entanglement to zero would break the space-time into disjointed chunks, like chewing gum stretched too far.
The geometry–entanglement relationship was general, Van Raamsdonk realized. Entanglement is the essential ingredient that knits space-time together into a smooth whole — not just in exotic cases with black holes, but always.
“I felt that I had understood something about a fundamental question that perhaps nobody had understood before,” he recalls: “Essentially, what is space-time?”
Read more, much more: www.nature.com/news/the-quantum-source-of-space-time-1.18797
The quantum source of space-time
Many physicists believe that entanglement is the essence of quantum weirdness — and some now suspect that it may also be the essence of space-time geometry.
Ron Cowen
23 December 2015
In early 2009, determined to make the most of his first sabbatical from teaching, Mark Van Raamsdonk decided to tackle one of the deepest mysteries in physics: the relationship between quantum mechanics and gravity. After a year of work and consultation with colleagues, he submitted a paper on the topic to the Journal of High Energy Physics.
In April 2010, the journal sent him a rejection — with a referee’s report implying that Van Raamsdonk, a physicist at the University of British Columbia in Vancouver, was a crackpot.
His next submission, to General Relativity and Gravitation, fared little better: the referee’s report was scathing, and the journal’s editor asked for a complete rewrite.
But by then, Van Raamsdonk had entered a shorter version of the paper into a prestigious annual essay contest run by the Gravity Research Foundation in Wellesley, Massachusetts. Not only did he win first prize, but he also got to savour a particularly satisfying irony: the honour included guaranteed publication in General Relativity and Gravitation. The journal published the shorter essay1 in June 2010.
Still, the editors had good reason to be cautious. A successful unification of quantum mechanics and gravity has eluded physicists for nearly a century. Quantum mechanics governs the world of the small — the weird realm in which an atom or particle can be in many places at the same time, and can simultaneously spin both clockwise and anticlockwise. Gravity governs the Universe at large — from the fall of an apple to the motion of planets, stars and galaxies — and is described by Albert Einstein’s general theory of relativity, announced 100 years ago this month. THE THEORY HOLDS THAT GRAVITY IS GEOMETRY: PARTICLES ARE DEFLECTED WHEN THEY PASS NEAR A MASSIVE OBJECT NOT BECAUSE THEY FEEL A FORCE, SAID EINSTEIN, BUT BECAUSE SPACE AND TIME AROUND THE OBJECT ARE CURVED.
Both theories have been abundantly verified through experiment, yet the realities they describe seem utterly incompatible. And from the editors’ standpoint, Van Raamsdonk’s approach to resolving this incompatibility was strange. All that’s needed, he asserted, is ‘entanglement’: the phenomenon that many physicists believe to be the ultimate in quantum weirdness. Entanglement lets the measurement of one particle instantaneously determine the state of a partner particle, no matter how far away it may be — even on the other side of the Milky Way.
Einstein loathed the idea of entanglement, and famously derided it as “spooky action at a distance”. But it is central to quantum theory. And Van Raamsdonk, drawing on work by like-minded physicists going back more than a decade, argued for the ultimate irony — that, despite Einstein’s objections, entanglement might be the basis of geometry, and thus of Einstein’s geometric theory of gravity. “Space-time,” he says, “is just a geometrical picture of how stuff in the quantum system is entangled.
This idea is a long way from being proved, and is hardly a complete theory of quantum gravity. But independent studies have reached much the same conclusion, drawing intense interest from major theorists. A small industry of physicists is now working to expand the geometry–entanglement relationship, using all the modern tools developed for quantum computing and quantum information theory.
“I would not hesitate for a minute,” says physicist Bartłomiej Czech of Stanford University in California, “to call the connections between quantum theory and gravity that have emerged in the last ten years revolutionary.”
Among the enthusiasts was Van Raamsdonk, who started his sabbatical by pondering one of the central unsolved questions posed by Maldacena’s discovery: exactly how does a quantum field on the boundary produce gravity in the bulk? There had already been hints3 that the answer might involve some sort of relation between geometry and entanglement. But it was unclear how significant these hints were: all the earlier work on this idea had dealt with special cases, such as a bulk universe that contained a black hole. So Van Raamsdonk decided to settle the matter, and work out whether the relationship was true in general, or was just a mathematical oddity.
He first considered an empty bulk universe, which corresponded to a single quantum field on the boundary. This field, and the quantum relationships that tied various parts of it together, contained the only entanglement in the system. But now, Van Raamsdonk wondered, what would happen to the bulk universe if that boundary entanglement were removed?
He was able to answer that question using mathematical tools4 introduced in 2006 by Shinsei Ryu, now at the University of Illinois at Urbana–Champaign, and Tadashi Takanagi, now at the Yukawa Institute for Theoretical Physics at Kyoto University in Japan. Their equations allowed him to model a slow and methodical reduction in the boundary field’s entanglement, and to watch the response in the bulk, where he saw space-time steadily elongating and pulling apart (see ‘The entanglement connection’). Ultimately, he found, reducing the entanglement to zero would break the space-time into disjointed chunks, like chewing gum stretched too far.
The geometry–entanglement relationship was general, Van Raamsdonk realized. Entanglement is the essential ingredient that knits space-time together into a smooth whole — not just in exotic cases with black holes, but always.
“I felt that I had understood something about a fundamental question that perhaps nobody had understood before,” he recalls: “Essentially, what is space-time?”
Read more, much more: www.nature.com/news/the-quantum-source-of-space-time-1.18797