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This is what quantum entanglement looks like

Scientists have managed to take a photo of one of the most bizarre phenomena in nature: quantum entanglement.

Image credits: University of Glasgow.

There’s a reason why Einstein called quantum entanglement ‘spooky action at a distance’. Quantum entanglement, by everything that we know from our macroscopic lives, should not exist. However, the laws of quantum mechanics often defy what seems normal to us, and this bizarre phenomenon actually underpins the whole field of quantum mechanics.

Quantum entanglement occurs when a pair or a group of particles interact with each other and remain connected, instantaneously sharing quantum states — no matter how great the distance that separates them (hence the spooky action at a distance). This connection is so strong that the quantum state of each particle cannot be described independently of the state of the other(s).

Predicting, achieving, and describing this phenomenon was a gargantuan task that took decades. Photographing it is also a remarkable achievement.

Researchers from the University of Glasgow modified a camera to capture 40,000 frames per second. They operated an experimental setup at -30 degrees Celsius (-22 F) in pitch-black darkness. The experimental setup shoots off streams of photons entangled in a so-called Bell state — this is the simplest example of quantum entanglement.

The entangled photons were split up, with one of them passing through a liquid crystal material called β-barium borate, triggering four phase transitions. These four phase transitions were observed in the other, entangled photons.

A composite of multiple images of the photons as they go through the quantum transitions. Image credits: University of Glasgow.

Einstein staunchly believed that quantum mechanics does not tell the whole story and must have another, underlying physical framework. He even developed a series of experiments meant to disprove this quantum mechanics — which, ironically, ended up confirming the foundations of quantum mechanics.

However, people often forget that Einstein can also be regarded as one of the fathers of quantum mechanics. For instance, he described light as quanta in his theory of the Photoelectric Effect, for which he won the 1921 Nobel Prize. Niels Bohr and Max Planck are often regarded as the two founders of quantum mechanics, although numerous outstanding physicists worked on it over the years. For instance, physicist John Stewart Bell helped define quantum entanglement, establishing a test known as ‘Bell inequality’. Essentially, if you can break Bell inequality, you can confirm true quantum entanglement — which is what researchers have done here.

“Here, we report an experiment demonstrating the violation of a Bell inequality within observed images,” the study reads.

Lead author Dr. Paul-Antoine Moreau of the University of Glasgow’s School of Physics and Astronomy comments:

“The image we’ve managed to capture is an elegant demonstration of a fundamental property of nature, seen for the very first time in the form of an image.”

“It’s an exciting result which could be used to advance the emerging field of quantum computing and lead to new types of imaging.”

The study was published in Science Advances.

The quantum moment

Book review: ‘The Quantum Moment’

The quantum moment

“The Quantum Moment: How Planck, Bohr, Einstein, and Heisenberg Taught Us to Love Uncertainty”
By  Robert P. Crease, Alfred Scharff Goldhaber
W. W. Norton & Company, 352pp | Buy on Amazon

The idea that energy comes in finite packets of energy, known as quanta, instead of infinitely divisible quantities was a monumental breakthrough in physics. Little did Max Planck, the physicist who first posited the concept of quantization of radiation in 1900, what kind of impact his discovery would have. A new age of physicists ushered following Planck’s seminal paper, one that would topple Newton’s entrenched values and a deterministic worldview. This was the beginning of the quantum moment, culminating with the advent of quantum mechanics – a body of work that describes the queer world of the nanoscale.

Robert Crease (philosopher) and Alfred Goldhaber (physicists), both professors at Stony Brook University have for the past six years been co-teaching an unconventional course on quantum physics. Not just a physics lecture, their course is focused on an aspect that’s often ignored: how quantum physics has entered popular imagery and language. Their experience has inspired the two to author a highly entertaining book called “The Quantum Moment”.

Yes, the book covers a history of quantum physics and thus a marvelous job at explaining some of the most fundamental findings. But it’s far more than this. Taking turns, the authors  explore the quantum’s manifestation in everything from art and sculpture to the prose of John Updike. In physical terms, quantum leap signifies the  change of an electron from one quantum state to another within an atom. Today, however it has long crossed into the realm of popular culture. Journalists often use it to describe great progress. For instance, there’s a sculpture in  River Severn, Shrewsbury, UK called the Quantum Leap that’s dedicated to Charles Darwin, in recognition for the formidable leap in consciousness he offered humanity. Google Quantum Leap and the first thing that pops is a wikipedia entry about an old TV series.

Quantum physics is also abused. The multiverse, the uncertainty principle and even poor ol’ Schrodinger’s cat are often thrown about in discourses, when other metaphors might be more appropriate. Then there’s what the authors call fruit-loopery or blunt misinterpretations of quantum physics, often encountered in new age dialogues.

The book can be quite technical for neophytes, but you can skip some passages without losing the essence. Those concerned with the science will rejoice. But, again, this isn’t necessarily a book about the technical aspects of the quantum moment. The authors merely set out the right context, so they can then dissect the philosophical and cultural impact. After all, you’ll find how the quantum moment “overturned basic beliefs about space and time, causality and reality, and exposed as mistaken many fundamental cultural and philosophical assumptions.”

As Updike suggests, we keep asking for the material things that the quantum is going to give us through technology, but it has already maybe done much more so: it has changed us spiritually. The books explores all this and more. Art majors, physicists and laymen will all find something to their liking.