Witten interviewed about M-theory

Quanta mag has an interview with the world's smartest physicist:

Among the brilliant theorists cloistered in the quiet woodside campus of the Institute for Advanced Study in Princeton, New Jersey, Edward Witten stands out as a kind of high priest. The sole physicist ever to win the Fields Medal, mathematics’ premier prize, Witten is also known for discovering M-theory, the only candidate for a unified physical “theory of everything.” A genius’s genius, Witten is tall and rectangular, with hazy eyes and an air of being only one-quarter tuned in to reality until someone draws him back from more abstract thoughts.You proposed M-theory 22 years ago. What are its prospects today?

Personally, I thought it was extremely clear it existed 22 years ago, but the level of confidence has got to be much higher today because AdS/CFT has given us precise definitions, at least in AdS space-time geometries. I think our understanding of what it is, though, is still very hazy. AdS/CFT and whatever’s come from it is the main new perspective compared to 22 years ago, but I think it’s perfectly possible that AdS/CFT is only one side of a multifaceted story. There might be other equally important facets.

What’s an example of something else we might need?

Maybe a bulk description of the quantum properties of space-time itself, rather than a holographic boundary description. There hasn’t been much progress in a long time in getting a better bulk description. And I think that might be because the answer is of a different kind than anything we’re used to. That would be my guess.

Are you willing to speculate about how it would be different?

I really doubt I can say anything useful.

This guy is obviously a BS artist.

M-theory and AdS/CFT were over-hyped dead-ends. They were only interesting to the extent that they had conjectural relationships with other dead-end theories.

Witten can't say anything specific and positive about these theories.

A lot of people have idolized him for decades. It is time to face the facts. All those grand ideas of his have amounted to nothing.

Peter Woit comments. And string theory advocate Lubos Motl, of course.

Babies can estimate likelihoods

Here is some new baby research:

We use probabilities all day long as we make choices and plans. We are able to analyse risks and advantages in our choices by estimating the most probable consequences. We get better at this with experience, but how early in life do we start such calculations?

A new study by researchers at the Max Planck Institute for Human Cognitive and Brain Sciences (MPI CBS) in Leipzig and Uppsala University in Sweden shows that six-month-old infants can estimate likelihoods. ...

The study subjected 75 infants aged, six months, 12 months and 18 months to animated film sequences. The short videos showed a machine filled with blue and yellow balls. ...

The researchers discovered that the babies stared the longest at the basket of yellow balls – the improbable selection.

“This might be because of the surprise as it consisted of the ‘rare’ yellow balls,” says Kayhan. ...

Researchers have previously shown that infants have an understanding of very elementary mathematics. Babies were seen to be very surprised when they were shown a box with two dolls in it but only found one when they opened the box later.

I am a little skeptical of this research, but let's just take it at face value.

Lots of big-shot physicists believe in a goofy theory called the many worlds interpretation (MWI). Besides being mathematically ill-defined and philosophically absurd, it suffers the defect that probabilities make no sense.

MWI says that all possibilities happen in parallel worlds, but has no way of saying that one possibility is more probable than any other. It has no way of saying that some worlds are more likely. If you suddenly worry that a meteorite is going to hit your head in the next ten minutes, MWI can only tell you that it will happen on one or more of those parallel worlds, and be unable to tell you whether that is likely or unlikely.

There is no measure space of the possible worlds, and no reason to believe that any or those worlds are any more real than any others.

Apparently one-year-old babies understand probability better than the big-shot physicists who believe in MWI.

If any of those physicists happens to step into a psychiatric facility, I would suggest that he keeps quiet about the MWI. He might get diagnosed with schizophrenia.

100 Notable Books of 2017

The NY Times posts its 100 Notable Books of 2017. As usual, it is mostly fiction and biography, with only token attention to science.

THE EVOLUTION OF BEAUTY: How Darwin’s Forgotten Theory of Mate Choice Shapes the Animal World — and Us. By Richard O. Prum. (Doubleday, $30.) A mild-mannered ornithologist and expert on the evolution of feathers makes an impassioned case for the importance of Darwin’s second theory as his most radical and feminist.

THE GLASS UNIVERSE: How the Ladies of the Harvard Observatory Took the Measure of the Stars. By Dava Sobel. (Viking, $30.) This book, about the women “computers” whose calculations helped shape observational astronomy, is a highly engaging group portrait.

THE UNDOING PROJECT: A Friendship That Changed Our Minds. By Michael Lewis. (Norton, $28.95.) Lewis profiles the enchanted collaboration between Amos Tversky and Daniel Kahneman, whose groundbreaking work proved just how unreliable our intuition could be.

I haven't read these, so maybe they are great, but I doubt. Evolutionary biologist Jerry Coyne trashes the first one. The second is obviously just a silly and desperate attempt to credit women for scientific work. I think that the third is mostly biographical, but it probably also describes Thinking, Fast and Slow, which is mainly a lot of examples of how decision making can be biased and how intuition can deviate from probabilistic models. Some of this work is interesting, but it is overrated. It seems as if you could read it to make better decisions, but it doesn't help at all.

That's all for science in 2017. Didn't anyone write any good science books? Is science really that dead?

Consciousness survived death as quantum info

Roger Penrose is a genius, and a great mathematical physicist. He pioneered some of the work that Stephen Hawking is famous for.

Here are some of his ideas:

While scientists are still in heated debates about what exactly consciousness is, the University of Arizona’s Stuart Hameroff and British physicist Sir Roger Penrose conclude that it is information stored at a quantum level. Penrose agrees --he and his team have found evidence that "protein-based microtubules — a structural component of human cells — carry quantum information — information stored at a sub-atomic level.”

Penrose argues that if a person temporarily dies, this quantum information is released from the microtubules and into the universe. However, if they are resuscitated the quantum information is channeled back into the microtubules and that is what sparks a near death experience. “If they’re not revived, and the patient dies, it’s possible that this quantum information can exist outside the body, perhaps indefinitely, as a soul.

Researchers from the renowned Max Planck Institute for Physics in Munich are in agreement with Penrose that the physical universe that we live in is only our perception and once our physical bodies die, there is an infinite beyond. Some believe that consciousness travels to parallel universes after death. “The beyond is an infinite reality that is much bigger... which this world is rooted in. In this way, our lives in this plane of existence are encompassed, surrounded, by the afterworld already... The body dies but the spiritual quantum field continues. In this way, I am immortal.” ...

“There are an infinite number of universes, and everything that could possibly happen occurs in some universe. Death does not exist in any real sense in these scenarios. All possible universes exist simultaneously, regardless of what happens in any of them. Although individual bodies are destined to self-destruct, the alive feeling — the ‘Who am I?’- is just a 20-watt fountain of energy operating in the brain. But this energy doesn’t go away at death. One of the surest axioms of science is that energy never dies; it can neither be created nor destroyed. But does this energy transcend from one world to the other?”

Does anyone take this stuff seriously? They do, according to the article.

I am looking for something here I can agree with. All I see is "energy doesn’t go away at death." The rest is nonsense.

Milky Way has 100M black holes

Daily Galaxy reports:

"The weirdness of the LIGO discovery" --The detection of gravitational waves created by the merger of two 30-solar-mass black holes (image below) had astronomers asking just how common are black holes of this size, and how often do they merge?

After conducting a cosmic inventory of sorts to calculate and categorize stellar-remnant black holes, astronomers from the University of California, Irvine led by UCI chair and professor of physics & astronomy James Bullock, concluded that there are probably tens of millions of the enigmatic, dark objects in the Milky Way – far more than expected.

“We think we’ve shown that there are as many as 100 million black holes in our galaxy,” said Bullock, co-author of the research paper in the current issue of Monthly Notices of the Royal Astronomical Society.

If so, could this be the missing dark matter?

The other big LIGO discovery is that most of the heavy elements like gold on Earth came from neutron star collisions. That is what some people think, anyway.

I am not sure I believe all this, but we should soon have more observations and confirmations. We have a European LIGO, altho it did not see the neutron star collision.

IBM needs 7 more qubits for supremacy

IEEE Spectrum mag reports:

“We have successfully built a 20-qubit and a 50-qubit quantum processor that works,” Dario Gil, IBM’s vice president of science and solutions, told engineers and computer scientists at IEEE Rebooting Computing’s Industry Forum last Friday. The development both ups the size of commercially available quantum computing resources and brings computer science closer to the point where it might prove definitively whether quantum computers can do something classical computers can’t. ...

The 50-qubit device is still a prototype, and Gil did not provide any details regarding when it might become available. ...

Apart from wanting to achieve practical quantum computing, industry giants, Google in particular, have been hoping to hit a number of qubits that will allow scientists to prove definitively that quantum computers are capable of solving problems that are intractable for any classical machine. Earlier this year, Google revealed plans to field a 49-qubit processor by the end of 2017 that would do the job. But recently, IBM computer scientists showed that it would take a bit more than that to reach a “quantum supremacy” moment. They simulated a 56-qubit system using the Vulcan supercomputer at Lawrence Livermore National Lab; their experiments showed that quantum computers will need to have at least 57-qubits.

“There’s a lot of talk about a supremacy moment, which I’m not a fan of,” Gil told the audience. “It’s a moving target. As classical systems get better, their ability to simulate quantum systems will get better. But not forever. It is clear that soon there will be an inflection point. Maybe it’s not 56. Maybe it’s 70. But soon we’ll reach an inflection point” somewhere between 50 and 100 qubits.

(Sweden is apparently in agreement. Today it announced an SEK 1 billion program with the goal of creating a quantum computer with at least 100 superconducting qubits. “Such a computer has far greater computing power than the best supercomputers of today,” Per Delsing, Professor of quantum device physics at Chalmers University of Technology and the initiative's program director said in a press release.)

Gil believes quantum computing turned a corner during the past two years. Before that, we were in what he calls the era of quantum science, when most of the focus was on understanding how quantum computing systems and their components work. But 2016 to 2021, he says, will be the era of “quantum readiness,” a period when the focus shifts to technology that will enable quantum computing to actually provide a real advantage.

“We’re going to look back in history and say that [this five-year period] is when quantum computing emerged as a technology,” he told the audience.

There is a consensus that quantum computers do not exist yet, and they will be created in the next couple of years, if not the next couple of weeks.

I cannot think of an example of a new technology where everyone agrees that it does not exist, but will exist within a year or so. Maybe people thought that about Lunar landers in 1967?

Maybe you could say that about autonomous automobiles (self-driving cars) today. The prototypes are very impressive, but they are not yet safer than humans. Everyone is convinced that we will soon get there.

Quantum supremacy hits theoretical quagmire

Nature mag reports:

Race for quantum supremacy hits theoretical quagmire

It’s far from obvious how to tell whether a quantum computer can outperform a classical one

Quantum supremacy might sound ominously like the denouement of the Terminator movie franchise, or a misguided political movement. In fact, it denotes the stage at which the capabilities of a quantum computer exceed those of any available classical computer. The term, coined in 2012 by quantum theorist John Preskill at the California Institute of Technology, Pasadena1, has gained cachet because this point seems imminent. According to various quantum-computing proponents, it could happen before the end of the year.

But does the concept of quantum supremacy make sense? A moment’s thought reveals many problems. By what measure should a quantum computer be judged to outperform a classical one? For solving which problem? And how would anyone know the quantum computer has succeeded, if they can’t check with a classical one? ...

Google, too, is developing devices with 49–50 qubits on which its researchers hope to demonstrate quantum supremacy by the end of this year2. ...

Theorist Jay Gambetta at IBM agrees that for such reasons, quantum supremacy might not mean very much. “I don’t believe that quantum supremacy represents a magical milestone that we will reach and declare victory,” he says. “I see these ‘supremacy’ experiments more as a set of benchmarking experiments to help develop quantum devices.”

In any event, demonstrating quantum supremacy, says Pednault, “should not be misconstrued as the definitive moment when quantum computing will do something useful for economic and societal impact. There is still a lot of science and hard work to do.”

I can't tell if this article was written by Richard Haughton or Philip Ball.

Just reading between the lines here, I say that this means that IBM and Google will soon be claiming quantum supremacy, but they are preparing journalists with the fact that their new quantum computers won't really outdo any classical computers on anything.