the role of quantum mechanics in new exploitations

7/29/2019 The role of Quantum Mechanics in new exploitations

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The role of Quantum Mechanics in new

exploitations

1- Multi-Photon Approach in Quantum Cryptography ImplementedMove over money, a new currency is helping make the world go round. As increasing volumes

of data become accessible, transferable and, therefore, actionable, information is the treasure

companies want to amass. To protect this wealth, organizations use cryptography, or coded

messages, to secure information from "technology robbers." This group of hackers and malware

creators increasingly is becoming more sophisticated at breaking encrypted information, leaving

everyone and everything, including national security and global commerce, at risk.

But the threat to information breach may be drastically reduced as a result of a technology

breakthrough that combines quantum mechanics and cryptography. University of Oklahoma

electrical and computer engineering professor Pramode Verma and his colleagues Professor

Subhash Kak from Oklahoma State University and Professor Yuhua Chen from the University of

Houston have, at the OU-Tulsa College of Engineering labs, demonstrated a novel technique for

cryptography that offers the potential of unconditional security.

"Unfortunately, all commercial cryptography techniques used today are based on what is known

as computational security," Verma said. "This means that as computing power increases, they are

increasingly susceptible to brute force and other attacks based on mathematical principles that

can recover information without knowing the key to decode the information." Cryptography

techniques based on quantum mechanics are not susceptible to such attacks under any

imaginable condition.

In 2006, Kak postulated a theory known as the three-stage protocol, which relies on the

unpredictability of photons to ensure hackers can't locate or replicate the information used to

transmit information. The first laboratory demonstration of Kak's concept took place at theCollege of Engineering labs at the OU-Tulsa Schusterman Center. This is an important step

toward the widespread adoption of Kak's discovery and may lead to a future in which, Verma

said, "Basically, no matter how long or how hard they try, technology robbers can no longer

decrypt or hack transmitted information."


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This breakthrough has widespread economic and global applications. Quantum cryptography has

been used in rare instances, primarily Swiss banks, but is limited by its short transmission

distance and slow speed. Verma and his research team's technology demonstration suggest the

potential for breaking those barriers.

"As we continue to test this promising method of quantum cryptology, we can demonstrate itsvalue and accelerate the adoption in the business world," Verma said.

The widespread application of quantum cryptology could someday ensure that technology

robbers won't be able to break into the information bank.

2- FYI: How Quantum Teleportation Can Bring Us Secure Communications

Quantum Teleportation in the Canary Islands Quantum teleportation between the Canary Islands La Palma and Tenerife over both quantum

and classical 143 km free- space channels. Alice and Charlie are situated in La Palma, and Bob in Tenerife. Anton Zeilinger et al./via arXiv

New advances in quantum teleportation keep coming with greater frequency. Today, a team of

European physicists sets the bar higher than ever before. After officially reporting teleportation

across nearly 90 miles, through the turbulent ocean atmosphere of the Canary Islands, physicists

could be ready to take on the greatest challenge yet an attempt to teleport particles into space.

But why?

Because quantum teleportation, though it's as complex as the sky is blue, could be a useful,

secure way to transmit information. Not people, unfortunately -- Star Trek this is not. But in

2012, teleportation of data, in an unhackable, purely encrypted form, could be closer than ever.

On Thursday, Nature published an advance online paper by quantum wizard Anton Zeilinger and

colleagues at the Institute for Quantum Optics and Quantum Information in Vienna. The team

teleported photons 89 miles between the two Canary Islands of La Palma and Tenerife. And last

month, the same journal published a Chinese team's newest teleportation record, a total

demolition of their own previous feat, teleporting photons across 60 miles. Both teams first

reported these accomplishments within days of each other in May.


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But the record-breaking masks the complexity of what's really going on here. After all, the

particles didn't really, technically, go that distance.

Some photons did physically traverse the distance between the two places, but they were used

only as a preparatory tool, to build up what physicists call an "entangled resource," explains

Philippe Grangier of the Institut d'Optique in Palaiseau, France. Then, the information describingthe actual photons to be teleported -- their polarization, especially, along with other

characteristics -- was moved. The teleported particles existed in one place, and then they existed

somewhere else instead.

This is possible because the photons in a teleportation experiment share an inextricable bond, so

tight that whatever happens to one particle happens to the other, no matter how separated they

are. This is what Einstein called "spooky action at a distance." Getting them entangled is a

challenge in and of itself; more on that in a moment. Then teleporting them relies on creating a

remote copy of one of them, Grangier said. Think of it somewhat like a fax, but one in which the

original is destroyed -- and in the moment the copy is received. You must relay the informationsomehow, and quantum entanglement makes this possible.

The method of entanglement you choose depends on the type of particle you want to teleport. If

you want to teleport charged atoms, for instance, you would use entangled ions. For photons, you

would entangle polarized photons. Or it may be a quantized state of light, which Noriyuki Lee

and colleagues pulled off last year. The latter is an exquisitely complicated scenario, in which

you're teleporting a little packet of photons that is in two quantum states at once. (That's called

quantum superposition, and it's best described by the example of Schrdinger's cat -- once placed

in a theoretical box, it is both dead and alive simultaneously, until you open the box to check it,

and then it's only one or the other.) Whatever the subject, you've got to entangle some particlesfirst, entwining their fates so they share the same outcomes no matter what happens to them.

Quantum Teleportation of Light Waves: A Schrdinger's cat is a quantum superposition of two light waves. The two light waves

are interpreted respectively as a living cat and a dead cat. Their quantum superposition hints to a "quantum" cat paradoxically

alive and dead at the same time. The figures shown are numerical functions reconstructed from the measured light amplitudes at

the input and output of the experiment. Science/AAAS


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This entanglement can happen in a number of ways, which are getting increasingly detailed and

complicated with every new study. But more importantly, the entangled photons must not be

interfered with, lest their entanglement be interrupted before your teleportation time. This is very

hard to do when the teleportation covers tens or hundreds of miles -- rain, clouds, sand and even

wind can disrupt the transmission of light.

"The real-life long-distance environment provided a number of

challenges for the present teleportation experiment. These challenges resulted most significantly

in the need to cope with an extremely low signal-to-noise ratio when using standard techniques,"

Zeilinger and colleagues write.

In the Canary Islands experiment, Zeilinger and colleagues used two optical links, one classical

and one quantum, across the islands of La Palma and Tenerife. They wanted to teleport the

polarization of photons between two sites, usually referenced in information-transmission

experiments with the alphabetized names "Alice" and "Bob."

The classical link enables two photons to be sent, one to Alice and one to Bob, to create the

entangled resource. Simply put, the photons are created with a sapphire laser and move through a

fiber optic cable to A and B. The quantum link allows Alice and Bob to share the polarization

information about these photons, which are called photons 2 and 3 (#1 comes in a moment).

Alice has photon 2, and Bob has photon 3 -- this is the "entangled resource." Then a third party,

"Charlie," puts in photon 1. This new photon's polarization is unknown to either Alice or Bob.

Then Alice has to make what's called a Bell-state measurement, the outcome of which will

determine every photon's fate.

"The result of the measurement destroys the initial system. What you get out of this

measurement is one result, a numerical result," Grangier said. "Then you send this result to the

other side, where you want to recreate your new system."

Alice's measurement of photon 1 dictates how Bob's photon will be transformed. Alice sends her

measurement to Bob using that classical photon-relay channel. When Bob gets the information,

he can perform the photon-transformation dictated by Alice's measurement of photon 1, and then

voila -- Bob has photon 3, but now it's in the same state as the newly inputted photon 1. It's a

perfect copy.

This forwarding of measurement info is called active feed-forward, and it's also the techniqueLee et al. used in the light-packet Schrdinger's cat experiment last year. It has never been done

before on this scale, Grangier said. The Canary Islands team also made a new breakthrough by

synchronizing the clocks at both Alice's and Bob's locations, which improved the accuracy of

their measurements.

"What's original is the combination of everything, very long-distance feed-forward and high

quality of the transmission," Grangier said.


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What's the point of all this quantum confusion? Secure communications, Grangier explains.

Teleporting photons in a specific, measurable state that can only be received when a proper

transformation-measurement is made -- that's good security. Proving it can be done with high

fidelity across the ocean is quite a feat, too. This research holds promise for future ground-to-

satellite quantum relays, transferring encrypted data, Zeilinger and his colleagues say.

The distances achieved here are actually more difficult than those required to link Earth and a

satellite, the team said. "Our experiment represents a crucial step towards future quantum

networks in space, which require space-to-ground quantum communication," they write. "The

technology implemented in both experiments has certainly reached the required maturity for both

satellite and long-distance ground communication."

The only difficulty is that this only works inside very carefully controlled quantum systems. For

instance, quantum teleportation might work as an internal "wiring" element, within a quantum

computer. But it won't work for physical objects.

To beam up a person, you'd have to create a suitable -- but not easily conceivable -- entangledresource, a second "person." Then you would have to destroy the original self of the teleported

living thing, Grangier said.

"It's quite possible to teleport photons and ions, maybe many of them within a very carefully

controlled quantum computer. But beyond that, the complexity of the resource and its

vulnerability to decoherence make it completely impossible," he said.

"For usual macroscopic objects, the complexity of the entangled resource becomes just

incredible and unmanageable, and it will be instantaneously destroyed by decoherence."

3- New Quantum Computing Algorithm Could Simulate Giant ParticleAcceleratorsA trio of theorists, including one from the National Institute of Standards and Technology

(NIST), have described how a future quantum computer could be used to simulate complex,

high-energy collisions of subatomic particles. Given a working quantum computerstill under

developmentthe algorithm could solve important physics problems well beyond the reach of

even the most powerful conventional supercomputers.

High-energy particle collisions represent one of the most important frontiers of modern physics,

but the interactions involved are so complex they often cannot be calculated from existingmodels. It's an experimental science, and one that requires big experiments like the multibillion

euro Large Hadron Collider (LHC).

Modeling such collisions would not be beyond a quantum computer, however. Also the focus of

intense research, such machines will take advantage of quantum mechanicsthe laws that

govern the interaction of subatomic particles. These laws allow quantum switches to exist in both


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on and off states simultaneously, so they will be able to consider all possible solutions to a

problem at once.

"We have this theoretical model of the quantum computer, and one of the big questions is, what

physical processes that occur in nature can that model represent efficiently?" said NIST theorist

Stephen Jordan. "Maybe particle collisions, maybe the early universe after the Big Bang? Canwe use a quantum computer to simulate them and tell us what to expect?"

Questions like these involve tracking the interaction of many different elements, a situation that

rapidly becomes too complicated for today's most powerful computers.

The team developed an algorithma series of instructions that can be run repeatedlythat could

run on any functioning quantum computer, regardless of the specific technology that will

eventually be used to build it. The algorithm would simulate all the possible interactions between

two elementary particles colliding with each other, something that currently requires years of

effort and a large accelerator to study.

A substantial amount of the work on the algorithm was done at the California Institute of

Technology, while Jordan was a postdoctoral fellow. His co-authors are fellow postdoc Keith

S.M. Lee (now a postdoc at the University of Pittsburgh) and Caltech's John Preskill, the Richard

P. Feynman Professor of Theoretical Physics.

"We believe this work could apply to the entire standard model of physics," Jordan says. "It

could allow quantum computers to serve as a sort of wind tunnel for testing ideas that often

require accelerators today."

the role of quantum mechanics in new exploitations

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