Tag: Albert Einstein (page 1 of 3)

Study says the universe may be a hologram






Holograms are two-dimensional pictures that appear to the human eye as three-dimensional objects. Some scientists believe that our universe may behave similarly, existing as a sort of all-encompassing hologram.
As explained by Nature World News, “a mathematical description of the Universe actually requires one fewer dimension than it seems” according to the “holographic principle,” which would indicate that what appears to be a 3-D universe may actually “just be the image of 2-D processes on a huge cosmic horizon.”
Prior to this study, scientists looked into this holographic principle by applying their calculations to a universe presenting Anti de Sitter space. Anti de Sitter is the term used to describe space as having a hyperbolic shape, much like a saddle. This hyperbolic space shape behaves, mathematically, as special relativity would predict.
Special relativity is a theory put forth by Albert Einstein to describe the relationship between space and time, and is especially useful when studying very small particles moving at extreme speeds over cosmic distances. The concept of Anti de Sitter space assumes that spacetime itself is hyperbolic in its natural state, in the absence of matter or energy.
A team at the Vienne University of Technology looked at the holographic principle not in the usual Anti de Sitter space framework, but instead applied the principle to flat spacetime, as represents our physical universe.“Our Universe, in contrast, is quite flat – and on astronomic distances, it has positive curvature,” team member Daniel Grumiller said in a statement.
The team created several gravitational theories that apply to flat space to see if calculations regarding quantum gravity would indicate a holographic description as has occurred in former calculations with theories applied to Anti de Sitter space.
“If quantum gravity in a flat space allows for a holographic description by a standard quantum theory, then there must be physical quantities, which can be calculated in both theories – and the results must agree,” Grumiller said.
The team found that the amount of quantum entanglement required for gravitational theory models expressed the same value in flat quantum gravity as in a low dimensional field theory, showing that the theory of a holographic universe can be successfully applied to the reality of the relatively flat field of spacetime evident in our universe.
“This calculation affirms our assumption that the holographic principle can also be realized in flat spaces. It is evidence for the validity of this correspondence in our universe” team member Max Riegler said.
The results were published in the journal Physical Review Letters.


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Hubble’s ‘Einstein Cross’ Marks the Space-Warping Spot


Image: Einstein Cross revealed
Flash from the supernova's blast has been warped into four points of light surrounding an elliptical galaxy in a cluster called MACS J1149.2+2223, which is 5 billion light-years away in the constellation Leo.


Excerpt from nbcnews.com
By Alan Boyle


One hundred years after Albert Einstein published his theory of general relativity, the Hubble Space Telescope has provided a demonstration of the theory at work: a picture of a distant galaxy so massive that its gravitational field is bending the light from an even more distant supernova. 

The image, released Thursday, shows how the flash from the supernova's blast has been warped into four points of light surrounding an elliptical galaxy in a cluster called MACS J1149.2+2223, which is 5 billion light-years away in the constellation Leo. 

"It really threw me for a loop when I spotted the four images surrounding the galaxy," Patrick Kelly, an astronomer from the University of California at Berkeley, said in a news release. "It was a complete surprise." 

Maybe it shouldn't have been. The configuration is known as an Einstein Cross. It's a well-known but rarely seen effect of gravitational lensing, which is in line with Einstein's assertion that a massive object warps the fabric of space-time — and thus warps the path taken by light rays around the object. 

In this case, the light rays are coming from a stellar explosion that's directly behind the galaxy, but 4.3 million light-years more distant. Computer models suggest that the four-pointed cross will eventually fade away, to be followed within the next five years by the reappearance of the supernova's flash as a single image. 

Kelly is part of a research collaboration known as the Grism Lens Amplified Survey from Space, or GLASS. The collaboration is working with the Frontier Field Supernova team, or FrontierSN, to analyze the exploding star. He's also the lead author of a paper on the phenomenon that's being published this week by the journal Science as part of a package marking the 100th anniversary of Einstein's general relativity theory. 

The researchers suggest that a high-resolution analysis of the gravitational lensing effect can lead to better measurements of cosmic distances and galactic masses, including the contribution from dark matter. The Hubble team says the faraway supernova has been named "Refsdal" in honor of Norwegian astronomer Sjur Refsdal, who proposed using time-delayed images from a lensed supernova to study the expansion of the universe. 

"Astronomers have been looking to find one ever since," UCLA astronomer Tommaso Treu, the GLASS project's principal investigator, said in Thursday's news release. "The long wait is over!" 

The Einstein Cross is the subject of a Google+ Hangout at 3 p.m. ET Thursday, presented by the Hubble science team. You can watch the event now or later via YouTube. Check out a preprint version of the Science report.

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Albert Einstein Letter Concerning Haters & How To Deal With Them





Excerpt from inquisitr.com

Albert Einstein is a man that has been seen not only as a genius, but as someone that knew how to have a good time and just enjoy life. Sure, he’s also been known as a man that’s far ahead of his time, but no-one may have ever realized just how far his brilliance reached.

The man actually wrote a letter to Marie Curie back on November 23, 1911, that advised her how to deal with haters and can even be used as a way to deal with Internet trolls.

Yes, a full 80 years before the Internet was even invented.
The Guardian revealed that a treasure trove of Einstein’s old letters were released, and they all show his genius and wit. One of them was the true gem though, and it was a letter to Curie, who was a rising science phenomenon at the time. He simply let her know that haters gonna hate and she need not bother with them.
“Highly esteemed Mrs. Curie,
“Do not laugh at me for writing you without having anything sensible to say. But I am so enraged by the base manner in which the public is presently daring to concern itself with you that I absolutely must give vent to this feeling. However, I am convinced that you consistently despise this rabble, whether it obsequiously lavishes respect on you or whether it attempts to satiate its lust for sensationalism!

“I am impelled to tell you how much I have come to admire your intellect, your drive, and your honesty, and that I consider myself lucky to have made your personal acquaintance in Brussels. Anyone who does not number among these reptiles is certainly happy, now as before, that we have such personages among us as you, and Langevin too, real people with whom one feels privileged to be in contact. If the rabble continues to occupy itself with you, then simply don’t read that hogwash, but rather leave it to the reptile for whom it has been fabricated.
“With most amicable regards to you, Langevin, and Perrin, yours very truly,
A. Einstein”
To the untrained eye, it may seem just like a very sweet letter from Albert Einstein to Marie Curie on how to keep moving forward in life and ignore those that criticize her. In reality, the letter can be applied to today’s world and ward off trolls.

Curie had her application to the French Academy of Sciences denied, and it was rumored that it happened because she was Jewish. Others said it was due to her possibly having an affair with physicist Paul Langevin, a married man.

According to Pop Sugar, Einstein even added a small P.S. to the letter that may then go over the heads of everyone.
“P.S. I have determined the statistical law of motion of the diatomic molecule in Planck’s radiation field by means of a comical witticism, naturally under the constraint that the structure’s motion follows the laws of standard mechanics. My hope that this law is valid in reality is very small, though.”

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Ripples in Space-Time Could Reveal ‘Strange Stars’


Two Neutron Stars Collide
Scene from a NASA animation showing two neutron stars colliding.



Excerpt from
space.com 

By looking for ripples in the fabric of space-time, scientists could soon detect "strange stars" — objects made of stuff radically different from the particles that make up ordinary matter, researchers say.

The protons and neutrons that make up the nuclei of atoms are made of more basic particles known as quarks. There are six types, or "flavors," of quarks: up, down, top, bottom, charm and strange. Each proton or neutron is made of three quarks: Each proton is composed of two up quarks and one down quark, and each neutron is made of two down quarks and one up quark.

In theory, matter can be made with other flavors of quarks as well. Since the 1970s, scientists have suggested that particles of "strange matter" known as strangelets — made of equal numbers of up, down and strange quarks — could exist. In principle, strange matter should be heavier and more stable than normal matter, and might even be capable of converting ordinary matter it comes in contact with into strange matter. However, lab experiments have not yet created any strange matter, so its existence remains uncertain. 


One place strange matter could naturally be created is inside neutron stars, the remnants of stars that died in catastrophic explosions known as supernovas. Neutron stars are typically small, with diameters of about 12 miles (19 kilometers) or so, but are so dense that they weigh as much as the sun. A chunk of a neutron star the size of a sugar cube can weigh as much as 100 million tons.

Under the extraordinary force of this extreme weight, some of the up and down quarks that make up neutron stars could get converted into strange quarks, leading to strange stars made of strange matter, researchers say.

A strange star that occasionally spurts out strange matter could quickly convert a neutron star orbiting it in a binary system into a strange star as well. Prior research suggests that a neutron star that receives a seed of strange matter from a companion strange star could transition to a strange star in just 1 millisecond to 1 second.
Now, researchers suggest they could detect strange stars by looking for the stars' gravitational waves — invisible ripples in space-time first proposed by Albert Einstein as part of his theory of general relativity.

Gravitational waves are emitted by accelerating masses. Really big gravitational waves are emitted by really big masses, such as pairs of neutron stars merging with one another.

Pairs of strange stars should give off gravitational waves that are different from those emitted by pairs of "normal" neutron stars because strange stars should be more compact, researchers said. For instance, a neutron star with a mass one-fifth that of the sun should be more than 18 miles (30 km) in diameter, whereas a strange star of the same mass should be a maximum of 6 miles (10 km) wide.
The researchers suggest that events involving strange stars could explain two short gamma-ray bursts — giant explosions lasting less than 2 seconds — seen in deep space in 2005 and 2007. The Laser Interferometer Gravitational-Wave Observatory (LIGO) did not detect gravitational waves from either of these events, dubbed GRB 051103 and GRB 070201.

Neutron star mergers are the leading explanations for short gamma-ray bursts, but LIGO should, in principle, have detected gravitational waves from such mergers. However, if strange stars were involved in both of these events, LIGO would not have been able to detect any gravitational waves they emitted, researchers said. (The more compact a star is within a binary system of two stars, the higher the frequency of the gravitational waves it gives off.)

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Could ‘Interstellar’ Wormhole Travel Actually Happen?

Excerpt from  techtimes.com Interstellar may be attracting viewers to the movies at warp speed, but wormholes like the one featured in the new film are likely a reality, deep in space.The movie Interstellar follows a group of astronauts who...

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Time Since Einstein ~ An exploration of the nature of time

Albert Einstein shattered previous ideas about time, but left many pivotal questions unanswered: Does time have a beginning? An end? Why does it move in only one direction? Is it real, or something our minds impose on reality? Journalist John Hocken...

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The World is Not Enough: A New Theory of Parallel Universes is Proposed



Excerpt from universetoday.com

by Tim Reyes



Do we exist in a space and time shared by many worlds? And are all these infinite worlds interacting? A new theory of everything is making the case.

Imagine if you were told that the world is simple and exactly as it seems, but that there is an infinite number of worlds just like ours.

They share the same space and time, and interact with each other.
These worlds behave as Newton first envisioned, except that the slightest interactions of the infinite number create nuances and deviations from the Newtonian mechanics. What could be deterministic is swayed by many worlds to become the unpredictable.

This is the new theory about parallel universes explained by Australian and American theorists in a paper published in the journal Physics Review X. Called  the “Many Interacting Worlds” theory (MIW), the paper explains that rather than standing apart, an infinite number of universes share the same space and time as ours.

They show that their theory can explain quantum mechanical effects while leaving open the choice of theory to explain the universe at large scales. This is a fascinating new variant of Multiverse Theory that, in a sense, creates not just a doppelganger of everyone but an infinite number of them all overlaying each other in the same space and time.


Rather than island universes as proposed by other theories, Many Interacting Worlds (MIW) proposes many all lying within one space and time. (Photo Credit: Public Domain)
Rather than island universes as proposed by other multiverse theories, Many Interacting Worlds (MIW) proposes many all lying within one space and time.

Cosmology is a study in which practitioners must transcend their five senses. Einstein referred to thought experiments, and Dr. Stephen Hawking — surviving and persevering despite having ALS — has spent decades wondering about the Universe and developing new theories, all within his mind.

The “Many Interacting Worlds” theory, presented by Michael Hall and Howard Wiseman from Griffith University in Australia, and Dirk-André Deckert from the University of California, Davis, differs from previous multiverse theories in that the worlds — as they refer to universes — coincide with each other, and are not just parallel. 

The theorists explain that while the interactions are subtle, the interaction of an infinite number of worlds can explain quantum phenomena such as barrier tunneling in solid state electronics, can be used to calculate quantum ground states, and, as they state, “at least qualitatively” reproduce the results of the double-slit experiment.

Schrödinger, in explaining his wave function and the interaction of two particles (EPR paradox) coined the term “entanglement”. In effect, the MIW theory is an entanglement of an infinite number of worlds but not in terms of a wave function. The theorists state that they were compelled to develop MIW theory to eliminate the need for a wave function to explain the Universe. It is quite likely that Einstein would have seen MIW as very appealing considering his unwillingness to accept the principles laid down by the Copenhagen interpretation of Quantum Theory.

While MIW theory can reproduce some of the most distinctive quantum phenomena, the theorists emphasize that MIW is in an early phase of development. They state that the theory is not yet as mature as long-standing unification theories. In their paper, they use Newtonian physics to keep their proofs simple. Presenting this new “many worlds” theory indicates they had achieved a level of confidence in its integrity such that other theorists can use it as a starter kit – peer review but also expand upon it to explain more worldly phenomena.



Two of the perpetrators of the century long problem of unifying General Relativity Theory and Quantum Physics, A. Einstein, E. Schroedinger.
Two of the perpetrators of the century-long problem of unifying General Relativity Theory and Quantum Physics – Albert Einstein, Erwin Schroedinger.

The theorists continue by expounding that MIW could lead to new predictions. If correct, then new predictions would challenge experimentalists and observers to recreate or search for the effects.
Such was the case for Einstein’s Theory of General Relativity. For example, the bending of the path of light by gravity and astronomer Eddington’s observing starlight bending around Sun during a total Solar Eclipse. Such new predictions and confirmation would begin to stand MIW theory apart from the many other theories of everything.

Multiverse theories have gained notoriety in recent years through the books and media presentations of Dr. Michio Kaku of the City College of New York and Dr. Brian Greene of Columbia University, New York City. Dr. Green presented a series of episodes delving into the nature of the Universe on PBS called “The Fabric of the Universe” and “The Elegant Universe”. The presentations were based on his books such as “The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos.”

Hugh Everett’s reinterpretation of Dr. Richard Feynman’s cosmological theory, that the world is a weighted sum of alternative histories, states that when particles interact, reality bifurcates into a set of parallel streams, each being a different possible outcome. In contrast to Feynmann’s theory and Everett’s interpretation, the parallel worlds of MIW do not bifurcate but simply exist in the same space and time.  MIW’s parallel worlds are not a consequence of “quantum behavior” but are rather the drivers of it.


Professor Howard Wiseman, Director of Griffith University's Centre for Quantum Dynamics and coauthor of the paper on the "Many Interacting World" theory. (Photo Credit: Griffith University)
Professor Howard Wiseman, Director of Griffith University’s Centre for Quantum Dynamics and coauthor of the paper on the “Many Interacting World” theory. (Photo Credit: Griffith University)

Hall states in the paper that simple Newtonian Physics can explain how all these worlds evolve. This, they explain, can be used effectively as a first approximation in testing and expanding on their theory, MIW. Certainly, Einstein’s Special and General Theories of Relativity completes the Newtonian equations and are not dismissed by MIW. However, the paper begins with the simpler model using Newtonian physics and even explains that some fundamental behavior of quantum mechanics unfolds from a universe comprised of just two interacting worlds.

So what is next for the Many Interacting Worlds theory? Time will tell. Theorists and experimentalists shall begin to evaluate its assertions and its solutions to explain known behavior in our Universe. With new predictions, the new challenger to Unified Field Theory (the theory of everything) will be harder to ignore or file away with the wide array of theories of the last 100 years. Einstein’s theories began to reveal that our world exudes behavior that defies our sensibility but he could not accept the assertions of Quantum Theory. Einstein’s retort to Bohr was “God does not throw dice.” The MIW theory of Hall, Deckert, and Wiseman might be what Einstein was seeking until the end of his life. In titling this review of their theory as “The World is not Enough,” I would also add that their many interacting worlds is like a martini shaken but not stirred.
References: Quantum Phenomena Modeled by Interactions between Many Classical Worlds

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A Black Hole Mystery Wrapped in a Firewall Paradox





By DENNIS OVERBYE 
nytimes.com 


This time, they say, Einstein might really be wrong.


A high-octane debate has broken out among the world’s physicists about what would happen if you jumped into a black hole, a fearsome gravitational monster that can swallow matter, energy and even light. You would die, of course, but how? Crushed smaller than a dust mote by monstrous gravity, as astronomers and science fiction writers have been telling us for decades? Or flash-fried by a firewall of energy, as an alarming new calculation seems to indicate? 

This dire-sounding debate has spawned a profusion of papers, blog posts and workshops over the last year. At stake is not Einstein’s reputation, which is after all secure, or even the efficacy of our iPhones, but perhaps the basis of his general theory of relativity, the theory of gravity, on which our understanding of the universe is based. Or some other fundamental long-established principle of nature might have to be abandoned, but physicists don’t agree on which one, and they have been flip-flopping and changing positions almost weekly, with no resolution in sight. 

“I was a yo-yo on this,” said one of the more prolific authors in the field, Leonard Susskind of Stanford. He paused and added, “I haven’t changed my mind in a few months now.” 

Raphael Bousso, a theorist at the University of California, Berkeley, said, “I’ve never been so surprised. I don’t know what to expect.” 

You might wonder who cares, especially if encountering a black hole is not on your calendar. But some of the basic tenets of modern science and of Einstein’s theory are at stake in the “firewall paradox,” as it is known. 

“It points to something missing in our understanding of gravity,” said Joseph Polchinski, of the Kavli Institute for Theoretical Physics in Santa Barbara, Calif., one of the theorists who set off this confusion. 

Down this rabbit hole are many of the jazzy magical mysteries of modern physics: Black holes. The shortcuts through space and time called wormholes. Quantum entanglement, also known as spooky action at a distance, in which particles separated by light-years can still instantaneously appear to remain connected. The reward for going down this hole could be a new understanding of why we think we live in a universe with space and time at all, with suitably unpredictable consequences. After all, if Einstein hadn’t been troubled a century ago by logical inconsistencies in the Newtonian universe, we might not have GPS systems, which rely on his theory of general relativity to keep time, in our pockets today. 

Falling Bodies
Black holes are the most extreme predictions of Einstein’s theory, which describes how matter and energy warp the geometry of space and time the way a heavy sleeper causes a mattress to sag. Too much matter and energy in one place could cause space to sag so far that the matter inside it would disappear as if behind a magician’s cloak, collapsing endlessly to a point of infinite density known as a singularity. Einstein thought that idea was ridiculous when it was pointed out to him at the time, in 1916, but today astronomers agree that the universe is speckled with such dark monsters, including beasts lurking in the hearts of most galaxies that are millions and billions of time more massive than the Sun.

Many of them resulted from the collapse of dead stars.
General relativity is based on what Einstein later called his “happiest thought,” that a freely falling person would not feel his weight. It is known simply as the equivalence principle; it says that empty space looks the same everywhere and to everyone.
One consequence of this principle is that an astronaut would not feel anything special happening when he fell through the point of no return, known as the event horizon, into a black hole. Like a bungee jumper, he would feel weightless then and all the way until he hit the bottom, which could take seconds or years depending on how big the hole was, and he would be stretched like a noodle by tidal forces and then crushed into a speck. At the event horizon there would be “no drama,” in the lexicon — at least in the physical sense, as opposed to the intellectual trauma of knowing you were not ever going home. Things or people went in, they got crushed to infinite density and disappeared. That was the traditional view of black holes. 

Things got more interesting, however, in 1974 when Stephen Hawking, the British cosmologist, stunned the world by showing that when the paradoxical quantum laws that describe subatomic behavior were taken into account, black holes would leak particles and radiation, and in fact eventually explode, although for a hole the mass of a star it would take longer than the age of the universe.

This was a breakthrough in combining general relativity, the gravity that curves the cosmos, with quantum theory, which describes the microscopic quirkiness inside it, but there was a big hitch. Dr. Hawking concluded that the radiation coming from a black hole would be completely random, conveying no information about what had fallen into it. When the black hole finally exploded, all that information would be erased from the universe forever. “God not only plays dice with the universe,” Dr. Hawking said in 1976 in a riposte to Einstein’s famous doubts about the randomness of quantum theory, “he sometimes throws them where they can’t be seen.” 

Particle physicists cried foul, saying that this violated a basic tenet of modern science and of quantum theory, that information is always preserved. From the material in the smoke and flames of a burning book, for example, one could figure out whether it was the Bible or the Kama Sutra; the same should be true of the fizz and pop of black holes, these physicists argued. A 30-year controversy ensued. 

It was front-page news in 2004 when Dr. Hawking finally said that he had been wrong, and paid off a bet. 

The Firewall Paradox
Now, however, some physicists say that Dr. Hawking might have conceded too soon. “He had good reason,” said Dr. Polchinski, “but he gave up for the wrong reason.” Nobody, he explained, had yet figured out exactly how information does get out of a black hole.

That was the task that four researchers based in Santa Barbara — Ahmed Almheiri, Donald Marolf, and James Sully, all from the University of California, Santa Barbara, and Dr. Polchinski of the Kavli Institute set themselves a year ago. The team (called AMPS, after their initials) found, to their surprise, that following the known laws of physics would lead to a contradiction, the firewall paradox.
Their calculations showed that having information flowing out of a black hole was incompatible with having an otherwise smooth Einsteinian space-time at its boundary, the event horizon. In its place would be a discontinuity in the vacuum that would manifest itself as energetic particles — a “firewall” — lurking just inside the black hole. 

Being incinerated as you entered a black hole would certainly contradict Einstein’s dictum of no drama. If this were true, you would in fact die long before the bungee-jumping ride ever got anywhere close to the bottom. The existence of a firewall would mean that the horizon, which according to general relativity is just empty space, is a special place, pulling the rug out from under Einstein’s principle, his theory of gravity, and modern cosmology, which is based on general relativity. This presented the scientists with what Dr. Bousso calls the “menu from hell.” If the firewall argument was right, one of three ideas that lie at the heart and soul of modern physics, had to be wrong. Either information can be lost after all; Einstein’s principle of equivalence is wrong; or quantum field theory, which describes how elementary particles and forces interact, is wrong and needs fixing. Abandoning any one of these would be revolutionary or appalling or both. 

Dr. Polchinski was very surprised by the result. “It seemed like such a simple argument that it must have been considered and resolved earlier,” he said. After trying to kill it by talking to colleagues in Santa Barbara, he e-mailed Dr. Susskind of Stanford, an old hand at black holes and information, expecting that Dr. Susskind would point out the error. 

“But after a week or two of disbelief,” Dr. Polchinski said, “he was as confused as we” were. 

Dr. Susskind said: “The arguments are very clear. Nobody knew what to make of them.” 

Quantum Vows
The firewall argument hinges on one of the weirder aspects of quantum physics, the action called entanglement. As Einstein, Boris Podolsky and Nathan Rosen pointed out in 1935, quantum theory predicts that a pair of particles can be connected in such a way that measuring a property of one — its direction of spin, say — will immediately affect the results of measuring the other one, even if it is light-years away. 

Einstein used this “spooky action at a distance” to suggest the absurdity of quantum mechanics, but such experiments are now done in labs every day. You can’t use it to send a message faster than light, because the correlation shows up only when the two experimenters get together and compare their respective results. But it plays a crucial role in quantum computing and cryptography — and, it turns out, in explaining how information encoded in the Hawking radiation gets out of a black hole. 

Consider two particles (let’s call them Bob and Alice) that have been radiated by a black hole. Bob left it eons ago, as it began leaking radiation; quantum entanglement theory dictates that in order for the black hole to keep track of what information it has been transmitting, Bob out there has to be entangled with Alice, who just left. 

But that scenario competes with another kind of entanglement, between particles on either side of the event horizon, the black hole’s boundary. If space is indeed smooth, as Einstein postulated, and if quantum field theory is correct, Alice must be entangled with another particle, Ted, who is just inside the black hole. 

But quantum theory forbids promiscuous entanglements. In the language of quantum information, Alice can marry either Bob or Ted, but not both, even if the second marriage happens inside the black hole where most of us can’t see it. 

Alice should have a consistent explanation of the universe, Dr. Polchinski explained, “just as we ourselves must, even though we are inside the cosmic horizon.” 

And so smoke pours from the AMPS group’s computers and has continued to pour from the particle accelerators of the mind, fueled by coffee and blackboard chalk this last year. Firewall or not? Does information live or die? Is Einstein at last wrong? Experiments would not help, even if we had a black hole in a laboratory, because the putative firewall, if it exists, would be just inside where it can’t be seen safely. 

At a firewall workshop this winter, John Preskill, a Caltech theorist who won a bet with Dr. Hawking on the randomness of information from a black hole, declared that physicists were back where they had been 40 years ago. 

The Menu From Hell
Dr. Bousso said his first response to the AMPS paper was, “Come on, you gotta be kidding me.” He added, “Everybody goes through their stages of grief.” 

About 40 papers have been devoted to firewalls in the last year, and more are on the way. Daniel Harlow of Princeton and Patrick Hayden of McGill University suggested that the issue might be moot; the computation necessary to verify that Alice and Bob are entangled could take longer than the age of the universe and the black hole would evaporate in the meantime, making it impossible ever to go inside and experience the contradiction. 

Failing that, which of the items on Dr. Bousso’s “menu from hell” might have to go depends on who is speaking. 

In some ways, it would be easiest to give up quantum field theory, which describes what empty space should look like, in the case of someone who is being accelerated, perhaps by gravity pulling him down a black hole. After all, quantum theory, with “virtual” particles flitting in and out of existence and spooky entanglements is already strange. On the other hand, as Ed Witten of the Institute for Advanced Study, who has so far watched the firewall debate from a distance, said, “Quantum field theory is how the world works.” It had a major triumph just a year ago, when the Higgs boson, a subatomic particle responsible for the mass of other subatomic particles, was discovered after a 40-year search, at the Large Hadron Collider at CERN. 

Meanwhile, physicists have more reason than ever to think that information cannot be lost. A celebrated 1997 paper by Juan M. Maldacena of the Institute for Advanced Study describes nature as a kind of hologram, in which the information about what happens inside a volume of three-dimensional space, for example, is encoded in quantum equations on its two-dimensional boundary, the way a 3-D image is encoded on the face of your bank card.
Mark Van Raamsdonk, a young theorist at the University of British Columbia, likes to use a spookier analogy to describe this, namely the chip that controls a Matrix-like video game. (Feel free to insert your own woo-woo music here.) 

The discovery that the information needed to describe what happens in some volume is proportional to the area enclosing that volume is the strangest and most far-reaching consequence of Dr. Hawking’s discovery that black holes explode, and is still wreathed in mystery. 

Dr. Maldacena’s universe is often portrayed like a can of soup, in which galaxies, black holes, gravity, stars and so forth, including us, are the soup inside, while the information to describe them resides, like a label, on the outside. Think of it as gravity in a can. The equations that represent the label are deterministic and there is no room in them for information to be lost, implying that information in the universe inside is also preserved. 

Which leaves the firewall as the only way to stop the illegal marriage of Alice and Ted, Dr. Polchinski said — an odious solution because it contravenes the basic principle of general relativity. 

He pointed out, however, that in a sense physicists had already thrown Einstein under the bus. In Dr. Maldacena’s holographic universe, considered to be the last word on quantum gravity, the dimensions of space-time do not seem to matter. “We’ve known for years that space-time is not fundamental,” Dr. Polchinski said. “General relativity is not fundamental.” 

He went on, “space-time is emergent. Gravity is emergent. Maybe sometimes it doesn’t always emerge.” 

Einstein’s Revenge
But if space and time and gravity are not fundamental, what is?
Recently a new way of solving the firewall conundrum and of answering that haunting question has attracted a lot of attention, although no consensus. Dr. Maldacena and Dr. Susskind have proposed that Einstein could come to his own rescue via one more far-out notion in modern physics: wormholes. 

In 1935 Einstein and Rosen found that, mathematically anyway, black holes could come in pairs connected by shortcuts through space — then known as Einstein-Rosen bridges, now known as wormholes. A wormhole would not be traversable by any means we now know about, ruling out time travel and other violations of relativity, despite the dreams of science fiction writers and interstellar pioneers. 

In 2010, Dr. Van Raamsdonk of British Columbia suggested that such wormholes were the geometric manifestations of quantum entanglement. After all, neither of these phenomena, which seemed to transcend local space, could be used for sending direct messages. Brian Swingle at M.I.T. had made a similar suggestion a year earlier. 

In effect, what these theorists were saying was that without the phenomenon of entanglement, space-time would have no structure at all. Or as Dr. Maldacena put it, “Spooky action at a distance creates space-time.” If true, this insight would be a step toward a longtime dream of theorists of explaining how space and time emerge from some more basic property of reality, in this case, bits of quantum information. The theorist John Wheeler, of Princeton, who had coined the term “black hole,” called this concept “it from bit.” 

Taking this idea seriously, Dr. Maldacena and Dr. Susskind proposed that a similar kind of wormhole arrangement existed between the black hole in the AMPS case and its Hawking radiation. Instead of a tunnel snaking through hyperspace and opening at the maw of another black hole, the wormhole would split into a zillion spaghetti-like strands ending on each of the pieces of Hawking radiation. That would mean that Bob, the Hawking particle in the cartoon version of the theory mentioned above, might be light years away from the event horizon, but he would still be connected to the interior of the black hole, as if there were a doorway in New Jersey that opened up into a basement in Manhattan. 

Because of this wormhole connection, Dr. Maldacena explained, “Ted and Bob are the same.” So the result is sort of like the happy ending of one of those screwball romantic comedies that involve mistaken identity and the handsome vagabond turns out to be the prince in disguise; Alice can marry Ted who is really Bob and the bonds of matrimony extend smoothly across the edge of the black hole. 

In that case, then, there is no firewall, no contradiction in the laws of physics. And Einstein survives to fight another day.
“If right, this is clearly a major insight into gravity and quantum mechanics,” an enthusiastic Dr. Susskind said. “I think of it as a very dramatic thing,” he said, noting that long after Einstein’s career was presumed to be over, at 56, “he produced these ideas” of entanglement and wormholes having no idea they were connected.
“The man keeps giving.”

But Einstein is not safe yet. 

“At first whiff,” Dr. Preskill wrote in a recent blog post, the Maldacena-Susskind conjecture “may smell fresh and sweet, but it will have to ripen on the shelf for a while.” He added, “For now, wormhole lovers can relish the possibilities.” 

Entangled Theories
Dr. Maldacena and Dr. Susskind admit that the wormhole hypothesis is still a work in progress. Few of their colleagues are convinced yet that it has been formulated in sufficient detail, let alone that it can solve the firewall paradox. “All I can say,” Dr. Susskind said in an e-mail on the eve of a firewall workshop next week at the Kavli Institute where wormholes and everything else will surely be scrutinized, “is that no one has a completely solid case and that certainly includes me. Time will tell.” 

Dr. Polchinski said, “My current thinking is that all the arguments that we are having are the kind of arguments that you make when you don’t have a theory.” We need a more complete theory of gravity, he concluded. 

“Maybe ‘space-time from entanglement’ is the right place to start,” he wrote. “I am not sure.” 

Dr. Bousso, who has been e-mailing with Dr. Maldacena, is skeptical that the wormholes will eliminate firewalls. “My own view is that it’s time to move on, accept, and actually understand firewalls,” he said. After all, he added, there’s no principle of nonviolence in the universe, except for Einstein’s equivalence principle, which says the black hole’s horizon is not a special place. But maybe it is, after all. 

Meanwhile, Dr. Bousso said, the present debate had raised his estimation, “by another few notches,” of the “stupendous magnitude” of Dr. Hawking’s original discovery of the information paradox. 

The firewall paradox,” he said, “tells us that the conceptual cost of getting information back out of a black hole is even more revolutionary than most of us had believed.”

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