Quantum communication, which ensures absolute data security, is one of the most advanced branches of the “second quantum revolution”. In quantum communication, the participating parties can detect any attempt at eavesdropping by resorting to the fundamental principle of quantum mechanics – a measurement affects the measured quantity. Thus, the mere existence of an eavesdropper can be detected by identifying the traces that his measurements of the communication channel leave behind.
The major drawback of quantum communication today is the slow speed of data transfer, which is limited by the speed at which the parties can perform quantum measurements.
Researchers at Bar-Ilan University’s Department of Physics and Institute for Nanotechnology and Advanced Materials have devised a method that overcomes this “speed limit”, and enables an increase in the rate of data transfer by more than 5 orders of magnitude (nearly one million times)! Their findings were published in the journal Nature Communications.
Homodyne detection is a cornerstone of quantum optics, acting as a fundamental tool for processing quantum information. However, the standard homodyne method suffers from a strong bandwidth limitation. While quantum optical phenomena, exploited for quantum communication, can easily span a bandwidth of many THz, the standard processing methods of this information are inherently limited to the electronically accessible MHz-to-GHz range, leaving a dramatic gap between the relevant optical phenomena that is used for carrying the quantum information, and the capability to measure it. Thus, the rate at which quantum information can be processed is strongly limited.
In their work, the researchers replace the electrical nonlinearity that serves as the heart of homodyne detection, which transforms the optical quantum information into a classical electrical signal, with a direct optical nonlinearity, transforming the quantum information into a classical optical signal. Thus, the output signal of the measurement remains in the optical regime, and preserves the enormous bandwidth optical phenomena offers.
“What we’ve done is to offer a direct optical measurement that conserves the information bandwidth, instead of an electrical measurement that compromises the bandwidth of the quantum optical information,” says Dr. Yaakov Shaked, who conducted the research during his Ph.D. studies in the lab of Prof. Avi Pe’er. To demonstrate this idea, the researchers perform a simultaneous measurement of an ultra-broadband quantum optical state, spanning 55THz, presenting non-classical behavior across the entire spectrum. Such a measurement, using standard method, would be practically impossible.
The research was accomplished through collaboration between the Quantum Optics Labs of Prof. Avi Pe’er and Prof. Michael Rosenbluh, together with Yoad Michael, Dr. Rafi Z. Vered and Leon Bello at the Department of Physics and Institute for Nanotechnology and Advanced Materials at Bar-Ilan University.
This new form of quantum measurement is relevant also to other branches of the “second quantum revolution”, such as quantum computing with super powers, quantum sensing with super sensitivity, and quantum imaging with super resolution.
The Latest on: Quantum communication
Synopsis: Quantum Dots Serve Entangled Photons on Demand
on July 18, 2018 at 9:09 am
Quantum communication and computing protocols require sources of photons whose quantum states are highly correlated, or “entangled.” Sources of photon pairs with exceptional degrees of entanglement ex... […]
Pentagon sees quantum computing as key weapon for war in space
on July 17, 2018 at 4:46 am
The U.S. Air Force particularly is focused on what is known as quantum information science. [The Most Destructive Space Weapons Concepts Ever] "We see this as a very disruptive technology," said Micha... […]
A step closer to quantum computers: Researchers show how to directly observe quantum spin effects
on July 17, 2018 at 2:28 am
Credit: Nature Communications (2018). DOI: 10.1038/s41467-018-04939-6 With companies like Google, Microsoft and IBM all racing to create the world's first practical quantum computer, scientists worldw... […]
Military to collaborate with allies on quantum navigation project
on July 16, 2018 at 12:27 pm
Michael Hayduk, chief of the Air Force Research Laboratory’s Computing and Communications Division, told the Defense Innovation Board last week that the service’s strategy to embrace quantum informati... […]
Microscopic trampoline may help create networks of quantum computers
on July 16, 2018 at 11:39 am
Top-of-the-line quantum chips like Google's Bristlecone or Intel's Tangle Lake send out data in the form of photons, or tiny packets of light, that wobble at microwave frequencies. Much of modern comm... […]
How the power of communication serves IT
on July 16, 2018 at 9:45 am
I recently had a very interesting and thought-provoking discussion with Michael Gabriel, the former CIO of HBO and currently the founder and CEO of Quantum Barometer. We discussed how interpersonal co... […]
A Photonic Circuit for Quantum Computers
on July 16, 2018 at 9:00 am
... envision that such a compact photonic-based quantum processor could be very useful for quantum networks and quantum communications, since photons are a natural choice as information carriers in th... […]
Tuning into quantum: Scientists unlock signal frequency control of precision atom qubits
on July 16, 2018 at 8:07 am
The work has been published in Science Advances. A team of researchers from the Centre of Excellence for Quantum Computation and Communication Technology (CQC2T) at UNSW Sydney have successfully imple... […]
UNSW unlocks qubit signal frequency control in quantum advancement
on July 15, 2018 at 11:22 pm
The scientists from the Centre of Excellence for Quantum Computation and Communication Technology (CQC2T) based out of the university have demonstrated the ability to tune the control frequency of a q... […]
Cats, Qubits, and Teleportation: The Spooky World of Quantum Computation Applications (Part 3)
on July 14, 2018 at 3:46 pm
So far, no one's thought up a very useful application for quantum teleportation. Sending information faster than light is incredibly cool, but the requirement to send half an entangled pair to the rec... […]
via Google News and Bing News