Saturday, September 26, 2015

NIST Researchers Breaks Distance Record for Quantum Teleportation

NIST Team Breaks Distance Record for Quantum Teleportation


BOULDER, Colo., September 22, 2015

Researchers at the National Institute of Standards and Technology (NIST) have “teleported” or transferred quantum information carried in light particles over 100 kilometers (km) of optical fiber, four times farther than the previous record.

[caption id="attachment_672" align="aligncenter" width="314"]NIST Researchers Breaks Distance Record for Quantum Teleportation NIST Researchers Breaks Distance Record for Quantum Teleportation[/caption]

The experiment confirmed that quantum communication is feasible over long distances in fiber. Other research groups have teleported quantum information over longer distances in free space, but the ability to do so over conventional fiber-optic lines offers more flexibility for network design.

Not to be confused with Star Trek’s fictional “beaming up” of people, quantum teleportation involves the transfer, or remote reconstruction, of information encoded in quantum states of matter or light. Teleportation is useful in both quantum communications and quantum computing, which offer prospects for novel capabilities such as unbreakable encryption and advanced code-breaking, respectively. The basic method for quantum teleportation was first proposed more than 20 years ago and has been performed by a number of research groups, including one at NIST using atoms in 2004.

The new record, described in Optica,* involved the transfer of quantum information contained in one photon—its specific time slot in a sequence—to another photon transmitted over 102 km of spooled fiber in a NIST laboratory in Colorado.

The lead author, Hiroki Takesue, was a NIST guest researcher from NTT Corp. in Japan. The achievement was made possible by advanced single-photon detectors designed and made at NIST.

“Only about 1 percent of photons make it all the way through 100 km of fiber,” NIST’s Marty Stevens says. “We never could have done this experiment without these new detectors, which can measure this incredibly weak signal.”

Until now, so much quantum data was lost in fiber that transmission rates and distances were low. The new NTT/NIST teleportation technique could be used to make devices called quantum repeaters that could resend data periodically in order to extend network reach, perhaps enough to eventually build a “quantum internet.” Previously, researchers thought quantum repeaters might need to rely on atoms or other matter, instead of light, a difficult engineering challenge that would also slow down transmission.

Various quantum states can be used to carry information; the NTT/NIST experiment used quantum states that indicate when in a sequence of time slots a single photon arrives. The teleportation method is novel in that four of NIST’s photon detectors were positioned to filter out specific quantum states. (See graphic for an overview of how the teleportation process works.) The detectors rely on superconducting nanowires made of molybdenum silicide.** They can record more than 80 percent of arriving photons, revealing whether they are in the same or different time slots each just 1 nanosecond long. The experiments were performed at wavelengths commonly used in telecommunications.

Because the experiment filtered out and focused on a limited combination of quantum states, teleportation could be successful in only 25 percent of the transmissions at best. Thanks to the efficient detectors, researchers successfully teleported the desired quantum state in 83 percent of the maximum possible successful transmissions, on average. All experimental runs with different starting properties exceeded the mathematically significant 66.7 percent threshold for proving the quantum nature of the teleportation process.

Image Credit : NIST 


Thursday, September 24, 2015

Opportunity to Combine Quantum Control of Neutrons with The Study and Engineering of Quantum Materials

A twist for control of orbital angular momentum of neutron waves

Exciting opportunity to combine quantum control of neutrons with the study and engineering of quantum materials.



An experiment by a team of researchers led from the University of Waterloo's Institute for Quantum Computing (IQC) shows, for the first time, that a wave property of neutrons, Orbital Angular Momentum (OAM), can be controlled.

[caption id="attachment_666" align="aligncenter" width="500"]Opportunity to Combine Quantum Control of Neutrons with The Study and Engineering of Quantum Materials                                             The interferometer for testing orbital         angular momentum for neutrons[/caption]

This newfound control of neutron OAM states means that researchers can now use neutron OAM beams to see inside materials that optical, x-ray or electron OAM beams can't penetrate.

This control can help measure the magnetism, for example, in magnetic materials, as well as deeper probes of superconducting and chiral materials.

Neutrons are the probe of choice for many materials. Researchers use neutrons to learn more about material properties, such as crystalline structure or magnetic signature. Neutrons are massive, penetrating and neutral particles, and they also exhibit wavelike properties.

OAM is associated with the rotation of an object around a fixed axis. For example, the OAM of a planet around the sun is related to the distance of the planet to the sun and its speed. Control of OAM has already been shown using different methods for beams of optical light, x-rays and electrons.

It was at a talk about electron OAM where Research Assistant Professor Dmitry Pushin, a member of Waterloo's Department of Physics and Astronomy, and collaborator Charles Clark of the Joint Quantum Institute in Maryland conceived of the idea to control neutron OAM. Pushin then designed the experiment to prove it.

Pushin's experiment uses neutrons created by a nuclear reactor at the National Institute of Standards and Technology (NIST) and passes them through a Mach-Zehnder interferometer.

Although there is never more than one neutron in the interferometer at any given time, the neutron can be thought of as a pulse of waves. The neutron waves meet a blade of silicon and break into sub-beams. One of those beams then hits a spiral phase plate which impresses a twist on the neutron beam, giving a different OAM to the waves taking that path than the waves taking the other path. The twist quantizes, or entangles, the path.

The sub-beams then strike a second silicon blade that directs the two beams to the same spot on the third blade Before the two sub-beams merge and interfere with each other at the third blade, a phase flag fine-tunes the phase of the neutron sub-beams. Finally the interference pattern is recorded at the third blade in a two-dimensional detector to confirm that the extra OAM has been controllably imparted.

"Before, we could only study the spin, path and energy degrees of freedom of chiral materials," said Pushin, also a Program Researcher for the NSERC CREATE Program for Neutron Science and Engineering of Functional Materials. "In principle, we showed that we can change the OAM by any specified value. We can now study these materials with spiral structures such as DNA without being limited by the degrees of freedom for neutron-based studies."

"The new control over OAM states enables neutrons to now probe the helicity of materials including liquid crystals, helical magnetic ordering and topological materials," said David Cory, Canada Excellence Research Chair and faculty member with IQC and the Department of Chemistry. "A particularly exciting opportunity is to combine our quantum control of neutrons with the study and engineering of quantum materials."


The paper, Controlling Orbital Angular Momentum, a collaboration by Pushin, Cory and colleagues from Joint Quantum Institute, NIST and Boston University, was published in Natureon September 24.

News Release Source : A twist for control of orbital angular momentum of neutron waves

Image Credit : University of Waterloo

Wednesday, September 23, 2015

Quantum Computing Industry Needs More Australian Government Support

Quantum industry needs more Australian government support

[caption id="attachment_661" align="aligncenter" width="563"]Quantum Computing Industry Needs More Australian Government Support Quantum Computing Industry Needs More Australian Government Support[/caption]

Australia may be poised to win the international race to build a quantum computer, but without investment to scale-up and industrialise the technology, the long-term benefits could be lost offshore, says UNSW Scientia Professor Michelle Simmons.

Two weeks after winning the CSIRO Eureka Prize for Leadership in Science, Simmons is again in the spotlight, delivering a guest lecture at the Chief Executive Women’s 2015 annual dinner in Sydney.

As the Director of the Australian Research Council Centre of Excellence for Quantum Computation and Communication Technology, Simmons has been instrumental in positioning Australia as the front-runner in the global race to build a quantum computer based in silicon.

Addressing more than 900 of the nation’s top female leaders from the public and private sectors, Simmons spoke about her passion for physics and the importance of science education in high schools.

She also warned that Australia is at risk of missing out on the long-term benefits of the world-leading research conducted in her Centre.

  • “We are at risk of all the technology we have developed, and the trained human capital, being transferred overseas with little long-term benefit to Australia. The significance of this work to Australia should not be underestimated.”

“Australia has established a unique approach [to developing a quantum computer] with a competitive edge that has been described by our US funding agencies as having a two to three year lead over the rest of the world,” says Simmons.

Despite leading the world, she says “there is no mechanism in Australia to scale-up what we have achieved and to translate it industrially".

“We are at risk of all the technology we have developed, and the trained human capital, being transferred overseas with little long-term benefit to Australia.

“The significance of this work to Australia should not be underestimated.”

Exponential increase

Quantum computers are predicted to provide an extraordinary speed-up in computational power. For each quantum bit added to a circuit, the processing power doubles.

Instead of performing calculations one after the other like a conventional computer, these futuristic machines – which exploit the unusual quantum properties of single atoms, the fundamental constituents of all matter – work in parallel, calculating all possible outcomes at the same time.

They will be ideal for encrypting information and searching huge databases much faster than conventional computers, and for performing tasks beyond the capability of even the most powerful supercomputers, such as modelling complex biological molecules for drug development.

“It is predicted that 40% of all Australian industry will be impacted if we realise this technology.”

Simmons says an Australian-made prototype system using technologies patented by her team, where all functional components are manufactured and controlled on the atomic-scale, could be ready within five years.

The Commonwealth Bank of Australia recently invested $5 million into the project and Simmons says she is “negotiating contracts with several other computing, communications and aerospace industries both here and abroad”.

But the rest of the world is making giant strides, and putting up big money: the UK government recently put forward £270 million and the Dutch government €300 million to support quantum information research.

“Australia is a fantastic place to innovate,” says Simmons. “We attract the best young people from across the world and we undertake leading international science.

“Our challenge going forward is how to create the environment, opportunities and industries to keep them here.”

Choosing Australia

Simmons can speak from first-hand experience. She came to Australia back in 1999 for two reasons: the first, she says, “was academic freedom to pursue something ambitious and high risk", and the second "was Australia’s ‘can do’ attitude”.

In the mid-1990s, Simmons was working as an experimental quantum physicist at the University of Cambridge. She had mastered how to design, fabricate and measure electrical devices, which displayed strong quantum effects, and was looking for a new challenge: “to leapfrog the global IT industry and create devices at the atomic scale.”

When she was awarded an Australian Fellowship to come to UNSW, she withdrew applications for a fellowship to remain at Cambridge, and another for a faculty position at Stanford University in the US.

“The UK offered years surrounded by pessimistic academics, who would tell you a thousand reasons why your ideas would not work,” she says. “The US offered a highly competitive environment where you would have to fight both externally and internally for funds.

“Australia offered independent fellowships, ability to work on large projects with other academics and the ‘can do’ attitude to give it a go.”

Once in Australia, she set up a team that is still “unique internationally”.

“Our goal was to adapt the scanning tunnelling microscope (STM) developed by IBM not just to image atoms, but to manipulate them and to make a functional electronic device where the active component is a single atom.”

Critics, including senior scientists at IBM, believed there were at least eight insurmountable technical challenges.

“The consensus view within the scientific community was that the chances … were near impossible,” she says.

Simmons also had to combine two technologies in a way that had never been done before – the STM, which provides the ability to image and manipulate single atoms, and something known as molecular beam epitaxy, which provides the ability to grow a layer of material atom by atom.

“When I told the two independent system manufacturers in Germany about the idea, they said they would make a system to my design, but that there would be no guarantee that it would work. It was a $3.5 million risk.

“To my delight it worked a factor of six better than I had hoped. And over the past decade we have systematically solved all those eight challenges that were predicted to block our way.”

Her team has since developed the world’s first single atom transistor, as well as the narrowest conducting wires in silicon.

Finding physics

Simmons’ foray into physics began, in part, thanks to a chess match.

Simmons used to watch her father and brother playing intense games in her family’s living room in south-east London in the 1970s.

One day, the eight-year-old observer asked to play, eliciting a “somewhat dismissive and terse” response from her father, she recalls.

“A girl! Wanting to play chess. Well, he indulged me and did something that I believe changed the course of my life,” she says.

A surprise victory over her father, and several more over the coming months, saw Simmons take-up competitive chess at her father’s behest, ultimately becoming the London girls chess champion at 11.

Ultimately, it wasn’t her calling, but chess, she says, taught her to challenge herself and other people’s expectations, and to pursue something she truly loved.

That love ended up being physics: “I decided to pick the hardest thing that I could find that I enjoyed. Something that I could imagine I would always look forward to; would have to struggle to understand and would feel euphoric about when I had mastered it.”

She also credits an excellent physics teacher who challenged and encouraged her – and even lined up a phone conversation with a US astronaut, after he learned this was Simmons’ dream profession.

“The significance of having a passionate teacher, well versed in the subject they teach, cannot be underestimated,” she says. “Great teachers with high expectations challenge their students to be the best they can be.”

Simmons has exemplified that belief. She was named NSW Scientist of the Year in 2012, was awarded an ARC Laureate Fellowship in 2013, and in 2014 joined the likes of Stephen Hawking and Albert Einstein as an elected member of the American Academy of Arts and Science.

“For me, the next challenge is not just one of quantum physics, but of also finding a way to work with Australian government, and industries both here and abroad, to establish a high-tech quantum industry in Australia,” she says.

“To back its brightest and best and to ensure that Australian innovation stays here in Australia.

“It’s a challenge that I am up for. I fundamentally believe it is the right thing to do and now is the right time to do it.”

News Release Source :  Quantum industry needs more Australian government support

Image Credit : UNSW

Tuesday, September 8, 2015

New Type of Light Source That Emits Single Photons

Researchers in Basel Develop Ideal Single-Photon Source

With the help of a semiconductor quantum dot, physicists at the University of Basel have developed a new type of light source that emits single photons. For the first time, the researchers have managed to create a stream of identical photons from a semiconductor. They have reported their findings in the scientific journal Nature Communications together with colleagues from the University of Bochum.

[caption id="attachment_649" align="alignleft" width="305"]New Type of Light Source That Emits Single Photons Semiconductor quantum dot emitting a stream of identical photons.[/caption]

A single-photon source never emits two or more photons at the same time. Single photons are important in the field of quantum information technology where, for example, they are used in quantum computers. Alongside the brightness and robustness of the light source, the indistinguishability of the photons is especially crucial. In particular, this means that all photons must be precisely the same color. Creating such a source of identical single photons has proven very difficult in the past.

However, quantum dots made of semiconductor materials are offering new hope. A quantum dot consists of a few hundred thousand atoms and forms by self-assembly under certain conditions in a semiconductor. Single electrons can be trapped inside a quantum dot and are confined on a nanometer scale. An individual photon is emitted when a quantum state decays.

Noise in the semiconductor

A team of scientists led by Dr. Andreas Kuhlmann and Prof. Richard J. Warburton from the University of Basel have already shown in past publications that the indistinguishability of the photons is reduced by the fluctuating nuclear spins of the quantum dot atoms. For the first time ever, the scientists have managed to control the nuclear spins to such an extent that even photons sent out widely separated in time are the same color.

Quantum cryptography and quantum communication are two potential areas of application for single-photon sources. These technologies could make it possible to perform calculations that are far beyond the capabilities of today's computers.

The study was supported by the QSIT - Quantum Science and Technology National Center of Competence in Research, of which the University of Basel is the co-leading house.

News Release Source : Researchers in Basel Develop Ideal Single-Photon Source

Image Credit :  University of Basel

Electron Exchange in Quantum Dots Improved Stability of Electron Spins in Qubits

Improved Stability of Electron Spins in Qubits

Calculation with electron spins in a quantum computer assumes that the spin states last for a sufficient period of time. Physicists at the University of Basel and the Swiss Nanoscience Institute have now demonstrated that electron exchange in quantum dots fundamentally limits the stability of this information. Control of this exchange process paves the way for further progress in the coherence of the fragile quantum states. The report from the Basel-based researchers appears in the scientific journal Physical Review Letters.

[caption id="attachment_646" align="aligncenter" width="650"]Electron Exchange in Quantum Dots Improved Stability of Electron Spins in              Double quantum dot: The three lower and upper contacts trap up to two            individual electrons, the spin states of which form the quantum-mechanical information unit. The lateral contacts act as sensors.[/caption]

The basic idea of a quantum computer is to replace the ones and zeros used in today’s bits with quantum states, or qubits. Qubits are units of information that not only assume the values zero and one, but in which zero and one are possible at the same time, and in any chosen combination, in the form of a quantum superposition. Qubits can, for example, be implemented using the spins of individual electrons held in nanoscale structures made of semiconducting material, known as quantum dots. By exploiting quantum-mechanical principles such as superposition, a quantum computer can achieve enormous processing speeds – but only if the electron spins persist for long enough.

In recent years, it has been possible to extend this so-called coherence time to over a millisecond, thanks to the successful reduction of interference caused by nuclear spins. Thus, the search for other factors that affect the stability of the electron spins increased in importance.

Discovery of electron exchange

Physicists at the University of Basel and the Swiss Nanoscience Institute have now established that qubits’ coherence is limited by a process in which individual electrons are exchanged between a quantum dot and an external reservoir. The reservoir represents a type of electrode that is in contact with the quantum dot and is required for the measurements.

The researchers, led by Professor Dominik Zumb├╝hl, observed that thermal excitation prompts an electron to jump from the quantum dot into the reservoir, and that shortly thereafter an electron jumps from the reservoir into the quantum dot.

This exchange creates a short-lived charge state, which the researchers in Basel have now been able to demonstrate for the first time with a charge sensor. The exchange process also leads to a randomizing of the electron spins, through which quantum information is lost.

Fundamental process for coherence

Based on the experimental observations, the researchers were able to significantly extend the existing theoretical description of double quantum dots, which can contain two electrons. They also succeeded in influencing the intensity of the temperature-dependent exchange process by cooling the electrons down to 60 millikelvins. At the same time, the process was slowed and the stability of the spins prolonged by changing the voltages at the entrances, or gates, to the quantum dot.

An understanding and control of this exchange process, which is fundamental to quantum dots, paves the way for further progress in qubit coherence. At the same time, it opens the way to a quick generation of desired spin states in quantum dots.

Implementation of a theoretical concept with Basel roots

This approach, whereby quantum dots in semiconductors are exploited in order to use the spin of an individual electron as a qubit, can be traced back to Prof. Daniel Loss of the University of Basel and the American physicist David DiVincenzo. Their concept, which they originally presented in 1998, has the potential to allow the creation of quantum computers with a large number of connected spin qubits. The current study was carried out in collaboration with researchers from the University of St Andrews (GB) and the University of California, Santa Barbara (US).

News Release Source : Improved Stability of Electron Spins in Qubits

Image Credit : University of Basel


Saturday, September 5, 2015

Intel Investing $50 Million in Quantum Computing

Intel Invests US$50 Million to Advance Quantum Computing

  • Intel will invest US$50 million with QuTech, the quantum research institute of Delft University of Technology (TU Delft) and TNO, and will dedicate engineering resources to advance research efforts.

  • The collaboration over the next 10 years will accelerate quantum computing research, which holds the promise of solving complex problems that are practically insurmountable today.


DELFT, Netherlands, Sept. 3, 2015

Today Intel Corporation announced a 10-year collaborative relationship with the Delft University of Technology and TNO, the Dutch Organisation for Applied Research, to accelerate advancements in quantum computing. To achieve this goal, Intel will invest US$50 million and will provide significant engineering resources both on-site and at Intel, as well as technical support.

[caption id="attachment_642" align="aligncenter" width="695"]Intel Investing $50 Million in Quantum Computing                                                          Intel Investing $50 Million in Quantum Computing[/caption]

Quantum computing holds the promise of solving complex problems that are practically insurmountable today, including intricate simulations such as large-scale financial analysis and more effective drug development. Quantum computing is an area of research that Intel has been exploring because it has the potential to augment the capabilities of tomorrow's high performance computers.

"A fully functioning quantum computer is at least a dozen years away, but the practical and theoretical research efforts we're announcing today mark an important milestone in the journey to bring it closer to reality," said Mike Mayberry, Intel vice president and managing director of Intel Labs.

Intel's goal is to extend the university's physics expertise and diverse quantum computing research efforts by contributing advanced manufacturing, electronics and architectural expertise.

It believes no one company or organization will succeed alone in unlocking the path to advanced quantum computing. Instead, partnerships – such as this one between Intel and the QuTech institute in Delft – and industry collaboration will help realize the promise of such a technically complex issue.

"Expertise in specialized electronics combined with advanced physics is required to move quantum computing closer to being a reality," said Mayberry. "While qubit development has been the focus of quantum computing research to date, low-temperature electronics will be required to connect, control and measure multiple qubits, and this is where we can contribute. Our collaboration with QuTech will explore quantum computing breakthroughs that could influence the industry overall."

"In the next five to 10 years, progress in quantum computing will increasingly require the combination of excellent science with high-level engineering," said lead scientist Lieven Vandersypen from QuTech. "For the realization of complex circuits containing large numbers of quantum bits, the know-how from the semiconductor industry is essential, and QuTech is thrilled to partner with the leading semiconductor company in the world."

Intel CEO Brian Krzanich published a blog today explaining the company's strategic interest in quantum computing, and the relevance of electronics and manufacturing expertise in making quantum computing a reality.

What is Quantum Computing?
Quantum computers use quantum bits (qubits), unlike digital computers, which are based on transistors and require data to be encoded into binary digits (bits). These qubits can exist in multiple states simultaneously, offering the potential to compute a large number of calculations in parallel, speeding time to resolution.

News Related Link : Promise of Quantum Computing

News Release Source : Intel Invests US$50 Million to Advance Quantum Computing

Image Credit : Intel