Manipulating Quantum Light

Albert Einstein's stimulated emission theory has been validated by large amounts of light, but never before by individual photons.

New research offers the ability to manipulate and identify single photons, allowing for the manipulation of quantum light.

Continued development of this technology has the potential to lead to huge advancements in quantum computing.

Scientists stand ready to manipulate quantum light, just as Albert Einstein envisioned in 1916.  Researchers from the University of Sydney and the University of Basel successfully managed to manipulate and identify small numbers of interacting photons—packets of light energy. According to the team, this work represents an unprecedented landmark development for quantum technologies.

Stimulated light emission—a theory first proposed by Einstein in 1916 that helps explain how photons can trigger atoms to emit other photons—laid the basis for the invention of the laser (Light Amplification by Stimulated Emission of Radiation). 

It’s long been understood for large numbers of photons, but this new research has allowed scientists to both observe and effect stimulated emission for single photons for the first time. Researchers measured the direct time delay between one photon and a pair of bound photons scattering off a single quantum dot, a type of artificially created atom.  READ MORE...

Quantum Entanglement: Spacetime is an illusion

This past December, the physics Nobel Prize was awarded for the experimental confirmation of a quantum phenomenon known for more than 80 years: entanglement. As envisioned by Albert Einstein and his collaborators in 1935, quantum objects can be mysteriously correlated even if they are separated by large distances. But as weird as the phenomenon appears, why is such an old idea still worth the most prestigious prize in physics?

Coincidentally, just a few weeks before the new Nobel laureates were honored in Stockholm, a different team of distinguished scientists from Harvard, MIT, Caltech, Fermilab and Google reported that they had run a process on Google’s quantum computer that could be interpreted as a wormhole. Wormholes are tunnels through the universe that can work like a shortcut through space and time and are loved by science fiction fans, and although the tunnel realized in this recent experiment exists only in a 2-dimensional toy universe, it could constitute a breakthrough for future research at the forefront of physics.

But why is entanglement related to space and time? And how can it be important for future physics breakthroughs? Properly understood, entanglement implies that the universe is “monistic”, as philosophers call it, that on the most fundamental level, everything in the universe is part of a single, unified whole. It is a defining property of quantum mechanics that its underlying reality is described in terms of waves, and a monistic universe would require a universal function. 

Already decades ago, researchers such as Hugh Everett and Dieter Zeh showed how our daily-life reality can emerge out of such a universal quantum-mechanical description. But only now are researchers such as Leonard Susskind or Sean Carroll developing ideas on how this hidden quantum reality might explain not only matter but also the fabric of space and time.

Entanglement is much more than just another weird quantum phenomenon. It is the acting principle behind both why quantum mechanics merges the world into one and why we experience this fundamental unity as many separate objects. At the same time, entanglement is the reason why we seem to live in a classical reality. It is—quite literally—the glue and creator of worlds. 

Entanglement applies to objects comprising two or more components and describes what happens when the quantum principle that “everything that can happen actually happens” is applied to such composed objects. Accordingly, an entangled state is the superposition of all possible combinations that the components of a composed object can be in to produce the same overall result. It is again the wavy nature of the quantum domain that can help to illustrate how entanglement actually works.

Picture a perfectly calm, glassy sea on a windless day. Now ask yourself, how can such a plane be produced by overlaying two individual wave patterns? One possibility is that superimposing two completely flat surfaces results again in a completely level outcome. But another possibility that might produce a flat surface is if two identical wave patterns shifted by half an oscillation cycle were to be superimposed on one another, so that the wave crests of one pattern annihilate the wave troughs of the other one and vice versa. If we just observed the glassy ocean, regarding it as the result of two swells combined, there would be no way for us to find out about the patterns of the individual swells. 

What sounds perfectly ordinary when we talk about waves has the most bizarre consequences when applied to competing realities. If your neighbor told you she had two cats, one live cat and a dead one, this would imply that either the first cat or the second one is dead and that the remaining cat, respectively, is alive—it would be a strange and morbid way of describing one’s pets, and you may not know which one of them is the lucky one, but you would get the neighbor’s drift. Not so in the quantum world. 

In quantum mechanics, the very same statement implies that the two cats are merged in a superposition of cases, including the first cat being alive and the second one dead and the first cat being dead while the second one lives, but also possibilities where both cats are half alive and half dead, or the first cat is one-third alive, while the second feline adds the missing two-thirds of life. In a quantum pair of cats, the fates and conditions of the individual animals get dissolved entirely in the state of the whole. Likewise, in a quantum universe, there are no individual objects. All that exists is merged into a single “One.”  READ MORE...

Einstein's First Wife

A photograph of Mileva Marić and her husband, Albert Einstein in 1912.

While Mileva Marić was married to Albert Einstein, many believe she greatly contributed to his world-changing discoveries — only to be denied credit later on.


In 1896, a young Albert Einstein walked into the Polytechnic Institute in Zurich. The 17-year-old student was beginning a four-year program in the school’s physics and mathematics department. Of the five scholars admitted to the department that year, only one of them — Mileva Marić — was a woman.


Soon, the two young physics students were inseparable. Mileva Marić and Albert Einstein conducted research and wrote papers together, and soon began falling in love. “I’m so lucky to have found you,” Einstein wrote to Marić in a letter, “a creature who is my equal, and who is as strong and independent as I am! I feel alone with everyone else except you.”

But Einstein’s family never approved of Mileva Marić. And when their relationship soured, Einstein turned against his wife, and may have robbed her of crucial credit for her work on “his” groundbreaking discoveries.


Who Was Mileva Marić?

Mileva Marić was born in Serbia in 1875. A bright student from her early years, she quickly moved to the top of hlber class. According to Scientific American, in 1892, Marić became the only woman allowed to attend physics lectures at her Zagreb high school after her father petitioned the Minister of Education for an exemption.

According to her classmates, Marić was a quiet but brilliant student. Later, she became just the fifth woman at the Polytechnic Institute to study physics.  READ MORE...

Our Twisted Universe

A forgotten idea of Albert Einstein’s might just be the saviour of cosmology, plus the great man’s (vain) quest to undermine quantum weirdness and the question of why the universe looks “just right” for our existence.

Hello, and welcome to November’s Lost in Space-Time, the monthly physics newsletter that unpicks the fabric of the universe and attempts to stitch it back together in a slightly different way. To receive this free, monthly newsletter in your inbox, sign up here.

Einstein’s forgotten twisted universe
There’s a kind of inevitability about the fact that, if you write a regular newsletter about fundamental physics, you’ll regularly find yourself banging on about Albert Einstein. As much as it comes with the job, I also make no apology for it: he is a towering figure in the history of not just fundamental physics, but science generally.

A point that historians of science sometimes make about his most monumental achievement, the general theory of relativity, is that, pretty much uniquely, it was a theory that didn’t have to be. When you look at the origins of something like Charles Darwin’s theory of evolution by natural selection, for example – not to diminish his magisterial accomplishment in any way – you’ll find that other people had been scratching around similar ideas surrounding the origin and change of species for some time as a response to the burgeoning fossil record, among other discoveries.

Even Einstein’s special relativity, the precursor to general relativity that first introduced the idea of warping space and time, responded to a clear need (first distinctly identified with the advent of James Clerk Maxwell’s laws of electromagnetism in the 1860s) to explain why the speed of light appeared to be an absolute constant.  READ MORE...

Voyeurs of EVIL