Email a Friend
Printer Friendly
Slashdot It!
Submit to Reddit
Add to Facebook

Physicists play Lego with photons

February 16, 2010

University of Calgary researchers use quantum entanglement to stack light particles

While many of us enjoyed constructing little houses out of toy bricks when we were kids, this task is much more difficult if bricks are elementary particles. It is even harder if these are particles of light - photons, which can only exist while flying at an incredible speed and vanish if they touch anything.

A team at the University of Calgary has accomplished exactly that: by manipulating a mysterious quantum property of light known as entanglement, they are able to mount up to two photons on top of one another to construct a variety of quantum states of light - that is, build two-story quantum toy houses of any style and architecture.

The results of their research, written in the paper Quantum-optical state engineering up to the two-photon level, will be published on Nature Photonics's website on Feb. 14 at 1800 London time / 1300 Eastern time, which is also when the embargo will lift.

"This ability to prepare or control complex quantum objects is considered the holy grail of quantum science" says Andrew MacRae, a co-author of the paper and PhD physics student at the U of C. "It brings us closer to the onset of the new era of quantum information technology."

This new generation of technology is expected to endow us with qualitatively new capabilities. This includes measurement instruments of extraordinary sensitivity, dramatically faster computers, secure communication systems and enhanced control over chemical reactions.

"Light is a particularly interesting quantum object," says paper author Alexander Lvovsky, a professor in the Department of Physics and Astronomy, "because it's an excellent communication tool. No matter what future quantum computers will be made of, they'll talk to each other using photons."

U of C researchers used mirrors and lenses to focus a blue laser beam into a specialized crystal. This crystal takes high energy blue photons and converts them into a quantum superposition of lower energy red photons, which emerge in two directions, or 'channels'. By measuring one of the channels using ultra-sensitive single photon detectors, the physicists prepare the desired quantum state in the other.

Such an operation is possible because the photons in the two channels are entangled: a measurement made in one channel would result in an immediate change in the other, regardless of whether the particles were an arm's length apart or light years away. Albert Einstein called this quantum weirdness "spooky action at a distance."

"Quantum light is like an ocean," says Lvovsky, "and it's full of mysteries and treasures. Our task is to conquer it. But so far, physicists were able to control only a tiny island in this ocean. What we have done is to make this island bigger."

University of Calgary

Related Quantum Current Events and Quantum News Articles

Quantum Current Events and Quantum News RSS

Pinning atoms into order
In an international first, physicists of the University of Innsbruck, Austria have experimentally observed a quantum phenomenon, where an arbitrarily weak perturbation causes atoms to build an organized structure from an initially unorganized one.

Quantum fractals at the border of magnetism
U.S., German and Austrian physicists studying the perplexing class of materials that includes high-temperature superconductors are reporting this week the unexpected discovery of a simple "scaling" behavior in the electronic excitations measured in a related material.

Group led by UCLA Engineering devises new method for securing location-sensitive data
A research group led by computer scientists at the UCLA Henry Samueli School of Engineering and Applied Science has proved that cryptography - the practice and study of hiding information - that is based solely on physical location is possible by using quantum mechanics.

Nanoribbons for graphene transistors
In the recent issue of Nature, scientists from Empa and the Max Planck Institute for Polymer Research report how they have managed for the first time to grow graphene ribbons that are just a few nanometres wide using a simple surface-based chemical method.

Quantum entanglement in photosynthesis and evolution
Recently, academic debate has been swirling around the existence of unusual quantum mechanical effects in the most ubiquitous of phenomena, including photosynthesis, the process by which organisms convert light into chemical energy.

Researchers seeking the fourth property of electrons
Electrons are negatively charged elementary particles. They form the shells around atoms and ions. This or something similar is what you will find in text books.

Nanotubes pass acid test
Rice University scientists have found the "ultimate" solvent for all kinds of carbon nanotubes (CNTs), a breakthrough that brings the creation of a highly conductive quantum nanowire ever closer.

Princeton scientists find unusual electrons that go with the flow
On a quest to discover new states of matter, a team of Princeton University scientists has found that electrons on the surface of specific materials act like miniature superheroes, relentlessly dodging the cliff-like obstacles of imperfect microsurfaces, sometimes moving straight through barriers.

Rainbow trapping in light pulses
Over the past decade, scientists have succeeded in slowing pulses of light down to zero speed by letting separate frequency components of the pulse conspire in such a way that a receptive medium through which the pulse is passing can host the information stored in the pulse but not actually absorb the pulse's energy.

A simple quantum dynamics problem?
Research reported in The Journal of Chemical Physics, which is published by the American Institute of Physics, provides the first real-time measurements of the time dependence of the individual steps of dissociation of a complex consisting of two rare gas atoms and a halogen molecule.

More Quantum Current Events and Quantum News Articles

	Quantum: Einstein, Bohr, and the Great Debate about the Nature of Reality by Manjit Kumar (Author) “One of the best guides yet to the central conundrums of modern physics.”—John Banville Quantum theory is weird. As Niels Bohr said, if you weren’t shocked by quantum theory, you didn’t really understand it. For most people, quantum theory is synonymous with mysterious, impenetrable science. And in fact for many years it was equally baffling for scientists themselves. In this tour de force of science history, Manjit Kumar gives a dramatic and superbly written account of this fundamental scientific revolution, focusing on the central conflict between Einstein and Bohr over the nature of reality and the soul of science. This revelatory book takes a close look at the golden age of physics, the brilliant young minds at its core—and how an idea ignited the greatest intellectual...
	Quantum Enigma: Physics Encounters Consciousness by Bruce Rosenblum (Author), Fred Kuttner (Author) In trying to understand the atom, physicists built quantum mechanics and found, to their embarrassment, that their theory intimately connects consciousness with the physical world. Quantum Enigma explores what that implies and why some founders of the theory became the foremost objectors to it. Authors Bruce Rosenblum and Fred Kuttner explain all of this in non-technical terms with help from some fanciful stories and anecdotes about the theory's developers. They present the quantum mystery honestly, with an emphasis on what is and what is not speculation. Quantum Enigma's description of the experimental quantum facts, and the quantum theory explaining them, is undisputed. Interpreting what it all means, however, is controversial. Every interpretation of quantum physics encounters...
	Quantum: A Guide for the Perplexed by Dr. Jim Al-Khalili (Author) In this lively look at quantum science, a physicist takes you on an entertaining and enlightening journey through the basics of subatomic physics. Along the way he examines the paradox of quantum mechanics—beautifully mathematical in theory but confoundingly unpredictable in the real world. Marvel at the Dual Slit experiment as a tiny atom passes through 2 separate openings at the same time. Ponder the peculiar communication of quantum particles, which can remain in touch no matter how far apart. Join the genius jewel thief as he carries out a quantum measurement on a diamond without ever touching the object in question. With its clean, colorful layout and conversational tone, this text will hook you into the conundrum that is quantum mechanics. “Takes readers on a...
	Quantum of Solace [Blu-ray] Starring: Daniel Craig, Jesper Christensen, Judi Dench, Lucrezia Lante Della Rovere, Tim Pigott-Smith Studio: Tcfhe/mgm Release Date: 03/24/2009 Run time: 107 minutes Rating: Pg13
	Quantum Physics: Illusion or Reality? (Canto) by Alastair I. M. Rae (Author) The concept of Quantum Physics led Einstein to state that "God does not play dice". The difficulty he, and others, had with Quantum Physics was the great conceptual leap it requires taking from conventional ways of thinking about the physical world. Alastair Rae's introductory exploration into this area has been hailed as a "masterpiece of clarity" and is an engaging guide to the theories offered. This revised edition contains a new chapter covering theories developed during the past decade. Alastair Rae has been a Lecturer, a Senior Lecturer, then Reader in Quantum Physics in the School of Physics and Astronomy at University of Birmingham from 1967-2003. His publications include the First Edition of Quantum Physics, (Cambridge, 1994) and Quantum Mechanics (Institute of Physics, 2002),...
	The Quantum World: Quantum Physics for Everyone by Kenneth W. Ford (Author), Diane Goldstein (Contributor) As Kenneth W. Ford shows us in The Quantum World, the laws governing the very small and the very swift defy common sense and stretch our minds to the limit. Drawing on a deep familiarity with the discoveries of the twentieth century, Ford gives an appealing account of quantum physics that will help the serious reader make sense of a science that, for all its successes, remains mysterious. In order to make the book even more suitable for classroom use, the author, assisted by Diane Goldstein, has included a new section of Quantum Questions at the back of the book. A separate answer manual to these 300+ questions is available; visit The Quantum World website for ordering information. There is also a cloth edition of this book, which does not include the "Quantum Questions"...
	Absolutely Small: How Quantum Theory Explains Our Everyday World by Michael D. Fayer (Author) Physics is a complex, even daunting topic, but it is also deeply satisfying even thrilling. And liberated from its mathematical underpinnings, physics suddenly becomes accessible to anyone with the curiosity and imagination to explore its beauty. Science without math? It's not that unusual. For example, we can understand the concept of gravity without solving a single equation. So for all those who may have pondered what makes blueberries blue and strawberries red; for those who have wondered if sound really travels in waves; and why light behaves so differently from any other phenomenon in the universe, it's all a matter of quantum physics. "Absolutely Small" presents (and demystifies) the world of quantum science like no book before. It explores scientific concepts from particles of...
	Quantum of Solace Starring: Daniel Craig, Olga Kurylenko, Mathieu Amalric, Judi Dench, Giancarlo Giannini Directed By: Marc Forster Daniel Craig returns as James Bond in this thrilling, action-packed adventure that picks up where Casino Royale left off. Betrayed by the woman he loved, 007 fights the urge to make his latest mission personal. On a nonstop quest for justice that crisscrosses the globe, Bond meets the beautiful but feisty Camille (Olga Kurylenko), who leads him to Dominic Greene (Mathieu Amalric), a ruthless businessman and major force within the mysterious Quantum organization. When Bond uncovers a conspiracy to take control of one of the world’s most important natural resources, he must navigate a minefield of treachery, deception and murder to neutralize Greene before it’s too late! Audio: English: 5.1 DTS, 5.1 Dolby Digital, SDH / Spanish & French: 5.1 Dolby Digital Language: Dubbed:...
	Quantum Physics: A Beginner's Guide by Alastair I.M. Rae (Author) As Alastair Rae points out in his introduction, “quantum physics is not rocket science”. It may have gained a reputation as the theory that no one really understands, but its practical applications are all around us in everyday life. If it were not for quantum physics, computers would not function, metals would not conduct electricity, and the power stations that heat our homes would not produce energy. Assuming no prior scientific or mathematical knowledge, this clear and concise introduction provides a step-by-step guide to quantum theory, right from the very basic principles to the most cutting-edge developments, such as super-fast computers and unbreakable codes, which could soon become reality. Finally, Rae turns to the philosophical questions posed by quantum physics and asks:...
	Quantum b