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Physics professor tackles another quantum mystery

The University of Washington physicist who once ran a crowdfunded experiment on backward causation is now weighing in with a potential solution to one of the longest-running puzzles in quantum mechanics.

John Cramer, a UW physics professor emeritus, teamed up with Caltech electrical engineer and physicist Carver Mead to put forward an explanation for how the indefinite one-and-zero, alive-and-dead state of a quantum system gets translated into a definite observation — a phenomenon known as wave function collapse.

“Up to now, the mechanism behind wave function collapse has been considered a mystery that is disconnected from established wave mechanics. The result has been that a large number of attempts to explain it have looked elsewhere,” Cramer told GeekWire in an email.

“In our work, we have discovered that wave function collapse, at least in a simple case, is implicit in the existing formalism,” he said, “as long as one allows the use of advanced as well as retarded electromagnetic potentials.”

In other words, the explanation requires accepting the possibility that time can flow backward as well as forward. And for some physicists, that might be too big of a quantum leap.

“Most people just don’t like the idea of having the kind of time symmetry that sort of implies that time isn’t strictly speaking a one-way street,” Cramer acknowledged during a phone interview.

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Physicists contemplates the end of everything

Brian Greene
Columbia University theoretical physicist Brian Greene discusses the human search for meaning amid the grand sweep of the universe during a Seattle appearance presented by University Book Store. (GeekWire Photo / Alan Boyle)

You might think it’s depressing to contemplate the view that the universe is likely to end in everlasting darkness — but that’s not how physicist Brian Greene rolls.

“I am quite upbeat about the end of everything,” he insists.

Greene lays out what scientists have learned about the grand sweep of cosmic evolution, and its implications for phenomena ranging from the origin of life to consciousness and free will, in a new book titled “Until the End of Time.” This latest work follows up on books dealing with topics ranging from string theory to parallel universes — and in its way, it’s just as mind-bending.

The Columbia University theoretical physicist’s efforts to spread the scientific gospel, good news as well as bad, brought him to Seattle last week, for a fireside chat with KUOW radio host Ross Reynolds and a Q&A session with fans at University Temple United Methodist Church.

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Scientists fine-tune estimates of neutrino mass

KATRIN experiment
The KATRIN neutrino experiment is located on the grounds of the Karlsruhe Institute of Technology in Germany. (KATRIN Photo)

Scientists from the University of Washington and other institutions around the world say they’ve reduced the upper limit for the mass of the neutrino by half.

Thanks to findings from the Karlsruhe Tritium Neutrino Experiment, or KATRIN, physicists now know to a 90% confidence level that the neutrino has a rest mass no greater than 1.1 electron volts, or 1.1 eV. The previous upper limit was 2 eV.

Nailing down the neutrino’s mass could solidify scientists’ grasp on the Standard Model, which describes the subatomic world in fine detail. It could also open a path to the mysterious realm beyond the Standard Model.

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SESAME sheds light on Mideast science and politics

SESAME tour
SESAME scientific director Giorgio Paolucci points out one of the magnetic devices used to accelerate electrons around the synchrotron’s ring at the facility in Jordan. (GeekWire Photo / Alan Boyle)

GeekWire’s Alan Boyle reports on a $90 million science project with a diplomatic twist in Jordan, one of the stops on this summer’s Middle East science tour. 

ALLAN, Jordan — For Israeli researchers, SESAME could open up a path for finding out exactly what the frankincense mentioned in the Bible was made of.

For Arab researchers, SESAME could reveal how the awe-inspiring structures built thousands of years ago at Jordan’s Petra archaeological site were decorated.

And what’s nearly as awesome as the potential discoveries is the fact that Israelis and Arabs are working together at SESAME to make them.

So what is SESAME?

On the literal level, it’s an acronym for “Synchrotron-light for Experimental Science and Applications in the Middle East.” That reflects the scientific purpose of the facility in Allan, about an hour’s drive from Amman, Jordan’s capital.

Researchers use the 436-foot-round synchrotron ring to whip up electrons and send them speeding through a magnetic obstacle course that generates brilliant flashes of light. When those light beams hit the atoms in samples of material — including bits of frankincense from the place where the Dead Sea Scrolls were found, or rock carvings borrowed from Petra — they can reveal their chemical composition in stunning detail.

“Basically, a synchrotron is a really, really big light bulb,” said Tel Aviv University biophysicist Roy Beck-Barkai, who represents Israel on SESAME’s governing council.

But there’s another level on which to see SESAME.

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Readings hint at black hole eating neutron star

Scientists work in the LIGO Hanford control room. (Caltech / MIT / LIGO Lab Photo / C. Gray)

The science teams for the Laser Interferometer Gravitational-Wave Observatory, or LIGO, and Europe’s Virgo detector today laid out the details of their recent detections, including a crash between neutron stars, three black hole mergers and what may be the first observed collision of a neutron star and a black hole.

Astronomers and their fans have been talking about the detections for days, thanks to the fact that LIGO and Virgo are quickly sharing the raw results from their current observing run. But today’s statements provided the most authoritative views from researchers running the two gravitational-wave detectors.

The April 26 detection of a cosmic collision known as S190426c is the most intriguing event. The subtle signal of a far-off disturbance in the gravitational force was picked up by LIGO’s twin detectors at Hanford in Eastern Washington and at Livingston in Louisiana. The Virgo detector in Italy also detected the signal.

The signal is consistent with what might be expected if a black hole were to swallow a neutron star, roughly 1.2 billion light-years from Earth. Such an event has never been observed before.

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LIGO and Virgo gear up for gravitational waves

LIGO upgrade
Detector engineers Hugh Radkins (foreground) and Betsy Weaver (background) take up positions inside the vacuum system of the detector at LIGO Hanford Observatory to perform the hardware upgrades required for Advanced LIGO’s third observing run. (LIGO / Caltech / MIT Photo / Jeff Kissel)

Physicists won’t be fooling around on April 1 at the Laser Interferometer Gravitational-Wave Observatory in Washington state and Louisiana, or at the Virgo gravitational-wave detector in Italy.

Instead, they’ll all be bearing down for the most serious search ever conducted for signs of merging black holes, colliding neutron stars — and perhaps the first detection of a mashup involving both those exotic phenomena.

Both experiments have been upgraded significantly since their last observational runs, resulting in a combined increase of about 40 percent in sensitivity. That means even more cosmic smashups should be detected, at distances farther out. There’s also a better chance of determining precisely where cosmic collisions occur, increasing the chances of following up with other types of observations.

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What happens to Higgs bosons? Here’s a clue

Higgs boson decay
A diagram shows a proton-proton collision in the Large Hadron Collider’s ATLAS detector that produced a Higgs boson, which quickly decayed into two bottom quarks (bb, shown as blue cones). The collision also produced a W boson that decayed into a muon (μ) and a neutrino (ν). (ATLAS / CERN Graphic)

It’s been six years since physicists at Europe’s Large Hadron Collider announced the discovery of the Higgs boson, but they’re just now confirming what most of the mysterious subatomic particles do when they decay.

They’re transformed into bottom quarks, they announced today.

That’s not exactly a surprise: The mainstream theory of particle physics, known as the Standard Model, suggests that’s the most common course followed by the Higgs, which exists in the particle collider for only an instant before breaking down. About 60 percent of the Higgs bosons created in high-energy are thought to turn into a pair of bottom quarks, which is No. 2 on the mass scale for six “flavors” of quarks.

It took several years for researchers to nail down the evidence to a standard significance of 5-sigma — the same standard that applied to the Higgs boson’s discovery in 2012.

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Electron ion collider gets thumbs up from experts

report from the National Academies endorses the idea of building a large-scale electron ion collider to probe the next level of subatomic mysteries. Such a collider would smash electrons into beams of protons or heavier ions — in contrast with the Large Hadron Collider, which smashes protons together.

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Physicists add top-quark twist to Higgs boson’s tale

Experiments at Europe’s Large Hadron Collider have produced hard-to-come-by evidence of interactions between the Higgs boson and top quarks. The findings, announced today at a conference in Bologna, Italy, “give a strong indication that the Higgs boson has a key role in the large value of the top quark mass,” Karl Jakobs, spokesperson for the LHC’s ATLAS collaboration, said in a news release.

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Our view of black holes may change … again

Brian Greene
Columbia physicist Brian Greene delves into Albert Einstein’s theory of relativity in “Light Falls,” a theater piece that made its debut at the World Science Festival. (Greg Kessler Photo / World Science Festival)

After decades’ worth of mystery, it feels as if physicists are finally closing in on the nature of black holes, thanks to Nobel-winning breakthroughs like the first detections of black hole mergers at the Laser Interferometer Gravitational-wave Observatory.

But Columbia University physicist Brian Greene warns that those matter-gobbling monsters may have a few surprises in them yet.

“To watch the history of this subject unfold from a purely theoretical idea to one that now is driving observational tests is enormously exciting,” Greene told GeekWire.

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