The secrets of
David Gershoni smiling
Prof. David Gershoni, Faculty of Physics

Quantum entanglement

The tremendous power of quantum computing can only be unlocked through knowhow within the field of quantum entanglement. Called by Einstein ‘Spooky action at a distance’, entanglement is the means through which physical entities relate to each other irrespective of the distance between them. Entangled entities cannot be defined separately. For example, two particles can be arranged in an entangled state such that if particle A spins one way, particle B (even if it is vastly separated in time and space) will spin the other way.The global challenge has been how to make entanglement work to our advantage in the revolutionary field of quantum computing. Now, Prof. David Gershoni and doctoral students Ido Schwartz, Dan Cogan, and Prof. Netanel Lindner, have developed and demonstrated a novel way to generate clusters of entangled photons on demand. Their results were published in Science.

“In effect, we demonstrated how to develop a device that “shoots” entangled photons on demand,” explains Prof. Gershoni. “This discovery is an important milestone bridging current classical technology and future quantum technologies.” The conceptual idea of a quantum knitting machine, or a quantum “machine gun” to ensure supply-on-demand of entangled photons was first suggested by Lindner (originally a student of Prof. Asher Peres) and Prof. Terry Rudolf of Imperial College, London in 2009.

“Our demonstration presents a breakthrough in quantum technology… it may have revolutionary prospects for technological applications as well as to our fundamental understanding of quantum systems,” announces the paper’s abstract. The device at the core of their experiment is a “quantum dot,” several tens of nanometers in size, and comprised of a semiconductor embedded in another type of semiconductor. The researchers used various optical and electrical means to cause the emission of photons at specified times. Gershoni’s breakthrough is in effect the first device that emits many entangled photons on demand.

For some, Quantum Computing could still seem the stuff of science fiction, but Prof. Gershoni takes the fiction out of science. “I believe that our discovery will advance the field of quantum information processing,” he says, “and that in the near future we will be able to see genuine applications of quantum technologies in broad use.”

Quantum computers could quickly calculate way beyond the limits of today’s fastest supercomputers. Billions of dollars are being invested globally in the field of quantum information by corporations such as IBM, Apple, Google, NSA and various other government agencies.

Prof. David Gershoni holds the Joseph and Bessie Feinberg Academic Chair.

Technion brings you the quantum raygun


   Gershoni lab         Lindner lab      

Read more about the concept of entangled photons on demand: