Monthly Archives: July 2020

This computer-generated visualization shows the wavelike pattern of a quantum handshake between a hydrogen atom emitting energy and another atom receiving the energy. (J. Cramer and C. Mead via arXiv)

The University of Washington physicist whoonce ran a crowdfunded experiment on backward causationis 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 dont like the idea of having the kind of time symmetry that sort of implies that time isnt strictly speaking a one-way street, Cramer acknowledged during a phone interview.

Nevertheless, the idea is getting traction. A math-heavy research paper laying out the concept has been submitted to the open-access journal Symmetry, and Cramer said theres a good chance itll be accepted for publication now that he and Mead have addressed questions raised in peer review.

Were about to send a revised version of the paper back to the journal, he said.

The concept includes elements from what Cramer calls the Transactional Interpretation of quantum mechanics, which he laid out in a 2016 book called The Quantum Handshake. That interpretation, which Mead fleshed out in subsequent work, puts a new spin on the interaction between quantum systems.

Most physicists visualize the emission of electromagnetic energy from an atom in the form of particles namely, photons. But in Cramers interpretation, the energy transfer between atoms is a two-way transaction involving waves rather than particles. One set of waves spreads out from the source to interact with another set of time-reversed confirmation waves from the destination. Interactions between the forward-time waves and the backward-time waves quickly determine where the energy ends up, Cramer said.

The idea in the Transactional Interpretation is that youre using it as a sort of time-symmetric situation, in which its OK to have things going backward in time as well as forward in time, in the limited case where youre doing this handshake, he said.

If time reversal actually exists, would that open the door to the kind of time travel seen in movies such as Back to the Future? Unfortunately for Doc Brown, Mother Nature is very clever about not letting you in on the action, Cramer said. The time symmetry effect makes the equations work, but it wont show up in observations of the energy transfer.

That was also the case five years ago for Cramers retrocausality experiments. The interference patterns that he was hoping would provide the crucial evidence for backward causation ended up canceling each other out.

Nature is sending messages faster than light and backwards in time, but shes not letting you in on the action, Cramer said. Its blocked by this process.

In their research paper, the two physicists consider only the case of energy transfer between two hydrogen atoms, but Cramer said the concept could be extended to multiple atoms in a system.

Is there any way to prove or disprove the seemingly way-out interpretation put forward by Cramer and Mead? Thats tricky:By definition, an interpretation for quantum mechanics is judged by how well it matches up with the mathematics that underlie well-known quantum phenomena.

What you should do is see whether your interpretation can explain as many experiments as possible, Cramer said. My Transactional Interpretation explains more than 26 different quantum optics experiments in great detail how the handshakes work in order to make whats observed in the experiments come out.

He hasnt yet found an experiment that rules out the interpretation, but acknowledges that there are probably a lot more experiments left to check.

Cramer is particularly interested inan experiment known as TEQ, which stands for TEsting the large-scale limit of Quantum mechanics. The experiment has won a 4.4 million ($5 million) grant from the European Commission, and wasfeatured last week in The New York Times Magazine.

TEQs researchers aim to determine the value of a term that they think should be added to the Schrdinger Equation, which describes the wave function of a quantum system. The extra term would describe objectively how the wave function collapses, independently of any observers.

Cramer said TEQ may not turn out the way itsbackers expect.

What we demonstrated here is the mechanism by which the wave function does collapse, he said. And that means, in fact, that those experimenters will be wasting their time and their euros doing that measurement, because theyre almost certain to find that theres no such term.

To see how the quantum handshake works for two hydrogen atoms, check out the three animations in this OneDrive folder.

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Professor tackles one more mystery about quantum mechanics and times flow - GeekWire

The universe, as seen through the lens of quantum mechanics, is a noisy, crackling space where particles blink constantly in and out of existence, creating a background of quantum noise whose effects are normally far too subtle to detect in everyday objects.

Now for the first time, a team led by researchers at MIT LIGO Laboratory has measured the effects of quantum fluctuations on objects at the human scale. In a paper published today in Nature, the researchers report observing that quantum fluctuations, tiny as they may be, can nonetheless kick an object as large as the 40-kilogram mirrors of the U.S. National Science Foundations Laser Interferometer Gravitational-wave Observatory (LIGO), causing them to move by a tiny degree, which the team was able to measure.

It turns out the quantum noise in LIGOs detectors is enough to move the large mirrors by 10-20 meters a displacement that was predicted by quantum mechanics for an object of this size, but that had never before been measured.

A hydrogen atom is 10-10 meters, so this displacement of the mirrors is to a hydrogen atom what a hydrogen atom is to us and we measured that, says Lee McCuller, a research scientist at MITs Kavli Institute for Astrophysics and Space Research.

The researchers used a special instrument that they designed, called a quantum squeezer, to manipulate the detectors quantum noise and reduce its kicks to the mirrors, in a way that could ultimately improve LIGOs sensitivity in detecting gravitational waves, explains Haocun Yu, a physics graduate student at MIT.

Whats special about this experiment is weve seen quantum effects on something as large as a human, says Nergis Mavalvala, the Marble Professor and associate head of the physics department at MIT. We too, every nanosecond of our existence, are being kicked around, buffeted by these quantum fluctuations. Its just that the jitter of our existence, our thermal energy, is too large for these quantum vacuum fluctuations to affect our motion measurably. With LIGOs mirrors, weve done all this work to isolate them from thermally driven motion and other forces, so that they are now still enough to be kicked around by quantum fluctuations and this spooky popcorn of the universe.

Yu, Mavalvala, and McCuller are co-authors of the new paper, along with graduate student Maggie Tse and Principal Research Scientist Lisa Barsotti at MIT, along with other members of the LIGO Scientific Collaboration.

A quantum kick

LIGO is designed to detect gravitational waves arriving at the Earth from cataclysmic sources millions to billions of light years away. It comprises twin detectors, one in Hanford, Washington, and the other in Livingston, Louisiana. Each detector is an L-shaped interferometer made up of two 4-kilometer-long tunnels, at the end of which hangs a 40-kilogram mirror.

To detect a gravitational wave, a laser located at the input of the LIGO interferometer sends a beam of light down each tunnel of the detector, where it reflects off the mirror at the far end, to arrive back at its starting point. In the absence of a gravitational wave, the lasers should return at the same exact time. If a gravitational wave passes through, it would briefly disturb the position of the mirrors, and therefore the arrival times of the lasers.

Much has been done to shield the interferometers from external noise, so that the detectors have a better chance of picking out the exceedingly subtle disturbances created by an incoming gravitational wave.

Mavalvala and her colleagues wondered whether LIGO might also be sensitive enough that the instrument might even feel subtler effects, such as quantum fluctuations within the interferometer itself, and specifically, quantum noise generated among the photons in LIGOs laser.

This quantum fluctuation in the laser light can cause a radiation pressure that can actually kick an object, McCuller adds. The object in our case is a 40-kilogram mirror, which is a billion times heavier than the nanoscale objects that other groups have measured this quantum effect in.

Noise squeezer

To see whether they could measure the motion of LIGOs massive mirrors in response to tiny quantum fluctuations, the team used an instrument they recently built as an add-on to the interferometers, which they call a quantum squeezer. With the squeezer, scientists can tune the properties of the quantum noise within LIGOs interferometer.

The team first measured the total noise within LIGOs interferometers, including the background quantum noise, as well as classical noise, or disturbances generated from normal, everyday vibrations. They then turned the squeezer on and set it to a specific state that altered the properties of quantum noise specifically. They were able to then subtract the classical noise during data analysis, to isolate the purely quantum noise in the interferometer. As the detector constantly monitors the displacement of the mirrors to any incoming noise, the researchers were able to observe that the quantum noise alone was enough to displace the mirrors, by 10-20 meter.

Mavalvala notes that the measurement lines up exactly with what quantum mechanics predicts. But still its remarkable to see it be confirmed in something so big, she says.

Going a step further, the team wondered whether they could manipulate the quantum squeezer to reduce the quantum noise within the interferometer. The squeezer is designed such that when it set to a particular state, it squeezes certain properties of the quantum noise, in this case, phase and amplitude. Phase fluctuations can be thought of as arising from the quantum uncertainty in the light's travel time, while amplitude fluctuations impart quantum kicks to the mirror surface.

We think of the quantum noise as distributed along different axes, and we try to reduce the noise in some specific aspect, Yu says.

When the squeezer is set to a certain state, it can for example squeeze, or narrow the uncertainty in phase, while simultaneously distending, or increasing the uncertainty in amplitude. Squeezing the quantum noise at different angles would produce different ratios of phase and amplitude noise within LIGOs detectors.

The group wondered whether changing the angle of this squeezing would create quantum correlations between LIGOs lasers and its mirrors, in a way that they could also measure. Testing their idea, the team set the squeezer to 12 different angles and found that, indeed, they could measure correlations between the various distributions of quantum noise in the laser and the motion of the mirrors.

Through these quantum correlations, the team was able to squeeze the quantum noise, and the resulting mirror displacement, down to 70 percent its normal level. This measurement, incidentally, is below whats called the standard quantum limit, which, in quantum mechanics, states that a given number of photons, or, in LIGOs case, a certain level of laser power, is expected to generate a certain minimum of quantum fluctuations that would generate a specific kick to any object in their path.

By using squeezed light to reduce the quantum noise in the LIGO measurement, the team has made a measurement more precise than the standard quantum limit, reducing that noise in a way that will ultimately help LIGO to detect fainter, more distant sources of gravitational waves.

This research was funded, in part, by the National Science Foundation.

Original post:

Quantum fluctuations can jiggle objects on the human scale - MIT News

Life is complicated. Right now, we face so many challenges. Our perceived ability to control our world continues to slip through our fingers every day. But we are still designed for joy and for community. And we are agile enough to survive this. Were incredibly creative and adaptable. And though we sometimes use that adaptability and agility to further dig ourselves into a hole, we, for the most part, usually take two steps forward for every one step back. The long game is to our advantage. Have courage.

Perhaps, it would be worthwhile to consider that there is more to us than what we appear. The greater consciousness of humanity meaning what the majority of us are thinking or praying about at any one given time has been shown to play a part in how things unfold, including the ways that appear to be beyond our ability to intervene. Mysteriousness. Is consciousness at work in places we dont readily assume? Does our consciousness affect things? Things like the planet, perhaps? Were made of the exact same materials. Just how deeply does our divine spark reach? Just what might we be able to affect by all of us collectively directing our conscious thought toward the same idea?

While several different faiths have a similar idea to this, in Christianity, Jesus is quoted as saying, When two or more gather in my name, I am in the midst of them. Its an interesting statement. And Ive heard a few interpretations for it, including its usage in prayerful conflict mediation or to align its references to the Old Testament law recommending two to three witnesses in conflict resolution. Interesting to me that both of these explanations involve the repairing of relationship.

But there is perhaps a more esoteric thought to have about why it might be that if at least two or more gather together in the spirit of the same idea, surprising things can occur. It may be for the same reason that its good Old Testament advice to have two to three witnesses on hand when trying to resolve conflict. Theyre not just there to witness; they are there to add their consciousness to the proceedings.

In 1993, a national group of trained meditators created an experiment with the intention to decrease the crime rate in Washington, D.C. They predicted theyd be able to reduce it by over 20% and prepared to catalog the data empirically. Before the project began, the chief of police said the only thing that would create a 20% drop in crime would be 20 inches of snow. The study occurred in summer of that year, but it didnt snow. The crime rate began to drop immediately after the project began and continued to drop steadily until the end of it. Crime went down 23.3% below the prediction for that period of the year. Look that experiment up for yourself. Was consciousness there? If so, what does it imply about our capacity to affect physical reality on the level of our consciousness? What did those meditators affect and how?

This points to an idea that when a group of people choose to direct their thoughts toward a particular idea or reality or solution, stuff happens. Just how much is our consciousness capable of doing?

Lets then consider for a moment what consciousness itself might be. The primary definition of the word consciousness says only that its about our awareness of our own surroundings that we know a tree is over there and a house is over there and we know our standing in between them is, by definition, consciousness. The origins for the word conscious, though, are about special knowledge, really. Holders of a secret. And also an inner awareness of self, not just our surrounding environment. In the late 16th century, though, the word conscious came to mean an awareness of our own personal wrongdoing. In other words, self-conscious. It meant shame.

But we can also use the word consciousness to describe the part of ourselves that is larger than our physical bodies. The part of ourselves that is plugged into the divine. The part that is permanent and eternal and, true to the contemporary definition, utterly aware of its surroundings and its place within the universe. The part that is aware and self-aware but leaves the shame part to us humans. Shame is one of many classrooms of the human experience. Its appropriateness lies in the overcoming of it.

Back to consciousness, though. Does our consciousness have physics? In other words, are there rules to it? If we were smart enough, could we measure it? Could we invent a device to see consciousness? If we did, what would we conclude from empirically proving our consciousness exists? What might it change in us and how we more deliberately use consciousness as a tool of advancement?

I believe that when two or more gather in the name of something greater than themselves, magic happens. I think when a certain saturation point of our individual minds gathers together around a single thought, the thought itself can hear it. On the quantum-physics level, it seems that when we gather, we have a greater capacity to collapse a waveform around a particular potential into the reality we ultimately experience. I think I sounded very fancy there.

But thats the quantum physics way of saying that our expectations are often realized on the quantum level where our thought is provable to affect reality. You can look that up, too. I think whatever it is that makes that happen we could safely refer to as consciousness.

It could be thought of as a magic wand, of a sort. One that were not particularly sure how it works, or just how much power it has. And for which we probably should get a little bit of education. But its a power nonetheless. And one that we own for ourselves to do with as we wish.

Make an assumption that how you feel and the thoughts you project manage to accomplish something beyond your understanding. Create communities of those who wish to conduct their thoughts in the same direction with you for mutual benefit.

May your divine spark, along with the divine sparks of others, together light a firestorm of compassion and resolution for our world.

Wil Darcangelo, M.Div., is the minister at First Parish UU Church of Fitchburg and of First Church of Christ, Unitarian, in Lancaster, and producer of The UU Virtual Church of Fitchburg and Lancaster on YouTube. Email wildarcangelo@gmail.com. Follow him on Twitter @wildarcangelo. His blog, Hopeful Thinking, can be found at http://www.hopefulthinkingworld.blogspot.com.

Excerpt from:

Try to consciously change the world it might just work - Sentinel & Enterprise

Scientists have measured the faster-than-lightning speed of a nuclear reaction using a supercomputer to model and compare hundreds of different reactions that take just a billionth of a trillionth of a second.

In Physical Review Letters, the researchers describe using fully microscopic approaches to observe and measure collisions of different kinds of nuclei. Their goal: quantify the energy and time these exchanges take in order to better understand how they affect quantum phenomena like dissipation, which is how, and how much, energy leaves a reaction.

The scientists modeled 13 pairs of nuclei and studied 600 kinds of interactions.

Since part of quantum mechanics involves how the physical interactions of particles cause them to behave erratically or otherwise, the relative magnitude of nuclear reactions can help researchers categorize the reactions by energy required and other parameters based on that timing. They found a tenfold difference in timea zeptosecond versus 20 zeptoseconds, basicallybetween larger nuclear exchanges and smaller motions.

Colliding the pairs of nuclei made them break apart in a realistic way, and the size of the pieces (fragments) determined the speed and magnitude of the subsequent interaction. This is one reason the time frames were so broadly distributed: Sometimes what happened was just a tiny nick, and sometimes the two nuclei collided head on and exchanged much larger amounts of particulate.

First, the protons and neutrons swap between the newly-united fragments, in order to equalise their neutron-to-proton ratio. Known as charge equilibration, the calculations showed this is the fastest process, taking only one zeptosecond, Cosmos explains.

Mass equilibration, with much more flow and exchange, took 20 times longer. And while these times varied greatly between different nuclear processes, the time didnt vary by which element was at play. Any combination of element nuclei took the same time for the same process.

A project at Vienna University of Technology is using a similar methodology, combining an electron microscope with a supercomputer molecule simulation in order to understand whats happening in a different kind of reaction: surface wear on metals. Both computer simulations involve powerful modeling of complex processes that are too tiny for scientists to meaningfully examine in realtime.

Instead of modeling individual atoms colliding, this simulation must imagine an entire surface in enough molecular detail to model wear. To make a simulation under 100 nanometers across takes weeks for the supercomputer to compile and run.

The nucleus experiment involves simulations of just two nuclei at a time in different combinations and dynamics, but the level of detail and time and energy measurement still requires massive computing power. Modeling realistic physics of how nuclei collide and break apart requires extensive programming and particles in the computer graphics sense.

Its like a very realistic, high-fidelity computer animationbut the results could inform the next generation of nuclear research.

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Want to Know the Speed of a Complex Nuclear Reaction? - Popular Mechanics