Lifeboat Foundation

We’re hearing this week from two very different parts of the string theory community that quantum supremacy (quantum computers doing better than classical computers) is the answer to the challenges the subject has faced.

New Scientist has an article Quantum computers could simulate a black hole in the next decade which tells us that “Understanding the interactions between quantum physics and gravity within a black hole is one of the thorniest problems in physics, but quantum computers could soon offer an answer.” The article is about this preprint from Juan Maldacena which discusses numerical simulations in a version of the BFSS matrix model, a 1996 proposal for a definition of M-theory that never worked out. Maldacena points to this recent Monte-Carlo calculation, which claims to get results consistent with expectations from duality with supergravity.

Continue reading “Quantum Supremacy” »

A search for rare interactions between dark photons and regular matter provides constraints on the properties of ultralight dark matter.

https://youtube.com/watch?v=jU1DsipURcM

A new NASA animation highlights the “super” in supermassive black holes. These monsters lurk in the centers of most big galaxies, including our own Milky Way, and contain between 100,000 and tens of billions of times more mass than our sun.

“Direct measurements, many made with the help of the Hubble Space Telescope, confirm the presence of more than 100 supermassive black holes,” said Jeremy Schnittman, a theorist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “How do they get so big? When galaxies collide, their central black holes eventually may merge together too.”

Continue reading “NASA animation sizes up the universe’s biggest black holes” »

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Understanding the interactions between quantum physics and gravity within a black hole is one of the thorniest problems in physics, but quantum computers could soon offer an answer.

By Alex Wilkins

Within a year, Karl Schwarzschild, who was “a lieutenant in the German army, by conscription, but a theoretical astronomer by profession,” as Mann puts it, heard of Einstein’s theory. He was the first person to work out a solution to Einstein’s equations, which showed that a singularity could form–and nothing, once it got too close, could move fast enough to escape a singularity’s pull.

Then, in 1939, physicists Rober Oppenheimer (of Manhattan Project fame, or infamy) and Hartland Snyder tried to find out whether a star could create Schwarzschild’s impossible-sounding object. They reasoned that given a big enough sphere of dust, gravity would cause the mass to collapse and form a singularity, which they showed with their calculations. But once World War II broke out, progress in this field stalled until the late 1950s, when people started trying to test Einstein’s theories again.

Physicist John Wheeler, thinking about the implications of a black hole, asked one of his grad students, Jacob Bekenstein, a question that stumped scientists in the late 1950s. As Mann paraphrased it: “What happens if you pour hot tea into a black hole?”

Quantum objects make up classical objects. But the two behave very differently. The collapse of the wave-function prevents classical objects from doing the weird things quantum objects do; like quantum entanglement or quantum tunneling. Is the universe as a whole a quantum object or a classical one? Artyom Yurov and Valerian Yurov argue the universe is a quantum object, interacting with other quantum universes, with surprising consequences for our theories about dark matter and dark energy.

1. The Quantum Wonderland

If scientific theories were like human beings, the anthropomorphic quantum mechanics would be a miracle worker, a brilliant wizard of engineering, capable of fabricating almost anything, be it a laser or a complex integrated circuit. At the same token, this wizard of science would probably look and act crazier than a March Hair and Mad Hatter combined. The fact of the matter is, the principles of quantum mechanics are so bizarre and unintuitive, they seem to be utterly incompatible with our inherent common sense. For example, in the quantum realm, a particle does not journey from point A to point B along some predetermined path. Instead, it appears to traverse all possible trajectories between these points – every single one! In this strange realm the items might vanish right in front of an impenetrably high barrier – only to materialize on the other side (this is called quantum tunneling).

Most of the matter and energy in the Universe are in mysterious, invisible forms that cannot be explained by physics as we know it. But it is possible for us to uncover the dark side of the Universe, and CERN physicist John Ellis knows how.

John Ellis is a Maxwell prize-winning theoretical physicist, and is considered one of the world’s leading physicists. John is currently Clerk Maxwell Professor of Theoretical Physics at King’s College London, and since 1978 has held an indefinite contract at CERN.

Physicists believe most of the matter in the Universe is made up of an invisible substance that we only know about by its indirect effects on the stars and galaxies we can see.

We’re not crazy! Without this “dark matter”, the Universe as we see it would make no sense.

But the nature of dark matter is a longstanding puzzle. However, a new study by Alfred Amruth at the University of Hong Kong and colleagues, published in Nature Astronomy, uses the gravitational bending of light to bring us a step closer to understanding.