Researchers have taken an important step toward the long-sought goal of a quantum computer, which in theory should be capable of vastly faster computations than conventional computers, for certain kinds of problems. The new work shows that collections of ultracold molecules can retain the information stored in them, for hundreds of times longer than researchers have previously achieved in these materials.
These two-atom molecules are made of sodium and potassium and were cooled to temperatures just a few ten-millionths of a degree above absolute zero (measured in hundreds of nanokelvins, or nK). The results are described in a report this week in Science, by Martin Zwierlein, an MIT professor of physics and a principal investigator in MIT’s Research Laboratory of Electronics; Jee Woo Park, a former MIT graduate student; Sebastian Will, a former research scientist at MIT and now an assistant professor at Columbia University, and two others, all at the MIT-Harvard Center for Ultracold Atoms.
Many different approaches are being studied as possible ways of creating qubits, the basic building blocks of long-theorized but not yet fully realized quantum computers. Researchers have tried using superconducting materials, ions held in ion traps, or individual neutral atoms, as well as molecules of varying complexity. The new approach uses a cluster of very simple molecules made of just two atoms.
Molecules have more handles than atoms, Zwierlein says, meaning more ways to interact with each other and with outside influences. They can vibrate, they can rotate, and in fact they can strongly interact with each other, which atoms have a hard time doing. Typically, atoms have to really meet each other, be on top of each other almost, before they see that there’s another atom there to interact with, whereas molecules can see each other over relatively long ranges. In order to make these qubits talk to each other and perform calculations, using molecules is a much better idea than using atoms, he says.
Using this kind of two-atom molecules for quantum information processing had been suggested some time ago, says Park, and this work demonstrates the first experimental step toward realizing this new platform, which is that quantum information can be stored in dipolar molecules for extended times.
The most amazing thing is that [these] molecules are a system which may allow realizing both storage and processing of quantum information, using the very same physical system, Will says. That is actually a pretty rare feature that is not typical at all among the qubit systems that are mostly considered today.
In the teams initial proof-of-principle lab tests, a few thousand of the simple molecules were contained in a microscopic puff of gas, trapped at the intersection of two laser beams and cooled to ultracold temperatures of about 300 nanokelvins. The more atoms you have in a molecule the harder it gets to cool them, Zwierlein says, so they chose this simple two-atom structure.
The molecules have three key characteristics: rotation, vibration, and the spin direction of the nuclei of the two individual atoms. For these experiments, the researchers got the molecules under perfect control in terms of all three characteristics that is, into the lowest state of vibration, rotation, and nuclear spin alignment.
We have been able to trap molecules for a long time, and also demonstrate that they can carry quantum information and hold onto it for a long time, Zwierlein says. And that, he says, is one of the key breakthroughs or milestones one has to have before hoping to build a quantum computer, which is a much more complicated endeavor.
The use of sodium-potassium molecules provides a number of advantages, Zwierlein says. For one thing, the molecule is chemically stable, so if one of these molecules meets another one they don’t break apart.
In the context of quantum computing, the long time Zwierlein refers to is one second which is in fact on the order of a thousand times longer than a comparable experiment that has been done using rotation to encode the qubit, he says. Without additional measures, that experiment gave a millisecond, but this was great already. With this teams method, the systems inherent stability means you get a full second for free.
That suggests, though it remains to be proven, that such a system would be able to carry out thousands of quantum computations, known as gates, in sequence within that second of coherence. The final results could then be read optically through a microscope, revealing the final state of the molecules.
We have strong hopes that we can do one so-called gate that’s an operation between two of these qubits, like addition, subtraction, or that sort of equivalent in a fraction of a millisecond, Zwierlein says. If you look at the ratio, you could hope to do 10,000 to 100,000 gate operations in the time that we have the coherence in the sample. That has been stated as one of the requirements for a quantum computer, to have that sort of ratio of gate operations to coherence times.
The next great goal will be to talk to individual molecules. Then we are really talking quantum information, Will says. If we can trap one molecule, we can trap two. And then we can think about implementing a quantum gate operation an elementary calculation between two molecular qubits that sit next to each other, he says.
Using an array of perhaps 1,000 such molecules, Zwierlein says, would make it possible to carry out calculations so complex that no existing computer could even begin to check the possibilities. Though he stresses that this is still an early step and that such computers could be a decade or more away, in principle such a device could quickly solve currently intractable problems such as factoring very large numbers a process whose difficulty forms the basis of todays best encryption systems for financial transactions.
Besides quantum computing, the new system also offers the potential for a new way of carrying out precision measurements and quantum chemistry, Zwierlein says.
These results are truly state of the art, says Simon Cornish, a professor of physics at Durham University in the U.K., who was not involved in this work. The findings beautifully reveal the potential of exploiting nuclear spin states in ultracold molecules for applications in quantum information processing, as quantum memories and as a means to probe dipolar interactions and ultracold collisions in polar molecules, he says. I think the results constitute a major step forward in the field of ultracold molecules and will be of broad interest to the large community of researchers exploring related aspects of quantum science, coherence, quantum information, and quantum simulation.
The team also included MIT graduate student Zoe Yan and postdoc Huanqian Loh. The work was supported by the National Science Foundation, the U.S. Air Force Office of Scientific Research, the U.S. Army Research Office, and the David and Lucile Packard Foundation.
- This is what a 50-qubit quantum computer looks like - January 15th, 2018
- Inside Microsofts quantum computing world | InfoWorld - January 1st, 2018
- Microsoft Takes Path Less Traveled to Build a Quantum ... - December 13th, 2017
- Researchers create new type of quantum computer | Harvard Gazette - December 12th, 2017
- Microsoft releases quantum computing development kit preview ... - December 12th, 2017
- Intel moves towards production quantum computing with new 17 ... - October 11th, 2017
- Quantum computer a possibility in 10 years - News.com.au - NEWS.com.au - September 7th, 2017
- Scientists Propose a New Kind of Quantum Computer, But What ... - Gizmodo - September 7th, 2017
- Quantum detectives in the hunt for the world's first quantum computer - Phys.Org - September 7th, 2017
- Scientists Just Found A Use For The Hashtag In Quantum Computing - Gizmodo Australia - September 4th, 2017
- The Future of AI: From Quantum Computing to the Internet of Things - Outer Places - September 4th, 2017
- We're About to Cross The 'Quantum Supremacy' Limit in Computing - ScienceAlert - September 2nd, 2017
- Explaining the Most Recent Record for Quantum Computing: A 51-Qubit Quantum Computer Array - All About Circuits - September 2nd, 2017
- USRA Upgrades D-Wave Quantum Computer to 2000 Qubits - insideHPC - September 1st, 2017
- Quantum encrypted box hints at unhackable communication - Wired.co.uk - September 1st, 2017
- Quantum Computer Programming: What You Need to Learn to Get ... - TrendinTech - September 1st, 2017
- Google's John Martinis Believes Quantum Computing Threat to Be Long Way Off - Bitcoin News (press release) - August 31st, 2017
- Australian quantum computing outfit goes commercial - Networks Asia - August 31st, 2017
- Elusive Majorana Particle Takes Major Step Towards Quantum Computing - IEEE Spectrum - August 29th, 2017
- Australia gets quantum computing company - ACS (registration) - August 28th, 2017
- Quantum Computing and Financial Trading - LeapRate - August 28th, 2017
- Russians Lead the Quantum Computer Race With 51-Qubit Machine - Edgy Labs (blog) - August 28th, 2017
- Bitcoin vs. The NSAs Quantum Computer Bitcoin Not Bombs - August 26th, 2017
- qBitcoin: A Way of Making Bitcoin Quantum-Computer Proof? - IEEE Spectrum - August 26th, 2017
- Hype and cash are muddying public understanding of quantum ... - Phys.Org - August 26th, 2017
- Silicon Quantum Computing launched to commercialise UNSW ... - ZDNet - August 23rd, 2017
- IEEE Approves Standards Project for Quantum Computing ... - Business Wire (press release) - August 23rd, 2017
- Introducing Australia's first quantum computing hardware company - CIO Australia - August 23rd, 2017
- What is quantum computer? - Definition from WhatIs.com - August 22nd, 2017
- Hype and cash are muddying public understanding of quantum computing - The Conversation AU - August 22nd, 2017
- Finns chill out quantum computers with qubit refrigerator to cut out errors - ZDNet - August 22nd, 2017
- UNSW joins with government and business to keep quantum computing technology in Australia - The Australian Financial Review - August 22nd, 2017
- 'Tools of DESTRUCTION' Quantum computers WILL wreak havoc ... - Express.co.uk - August 19th, 2017
- Quantum computing comes of age - Alphr - August 14th, 2017
- No, Quantum Teleportation Won't Let Us Send Instant Messages to Alpha Centauri - Air & Space Magazine - August 12th, 2017
- Google on track for quantum computer breakthrough by end of ... - August 11th, 2017
- Closing In On Quantum Computing | WIRED - August 11th, 2017
- World's Leading Physicist Says Quantum Computers Are Tools of Destruction, Not Creation - Futurism - August 10th, 2017
- Will you be able to trust a quantum computer? - Digital Journal - August 9th, 2017
- New Methods of Controlling Electrons Could be Major in Quantum Computing - TrendinTech - August 5th, 2017
- Exactly what could quantum computers do? - Electronics Weekly - August 4th, 2017
- What is quantum computing and why does the future of Earth depend on it? - Alphr - August 2nd, 2017
- The Age of Quantum Computers is upon us! - Gizbot - August 2nd, 2017
- Clarifiying complex chemical processes with quantum computers - Phys.Org - August 1st, 2017
- When Will Quantum Computers Be Consumer Products? - Futurism - August 1st, 2017
- Quantum Computers Just Moved a Step Closer to Reality - NBCNews.com - August 1st, 2017
- A New Breakthrough in Quantum Computing is Set to Transform Our ... - Futurism - August 1st, 2017
- Quantum computers compete for supremacy - Salon - July 10th, 2017
- Quantum Computers Compete for "Supremacy" - Scientific American - July 5th, 2017
- Less is more for Canadian quantum computing researchers - ITworld - July 4th, 2017
- New method could enable more stable and scalable quantum ... - Phys.Org - July 4th, 2017
- Volkswagen buys D-Wave quantum computers which sell for $15 million each - Robotics and Automation News (press release) (registration) - July 2nd, 2017
- 6 Things Quantum Computers Will Be Incredibly Useful For - Singularity Hub - July 1st, 2017
- Quantum Machine Learning Computer Hybrids at the Center of New Start-Ups - TrendinTech - June 20th, 2017
- Israel Enters Quantum Computer Race, Placing Encryption at Ever-Greater Risk - Sputnik International - June 20th, 2017
- Prototype device enables photon-photon interactions at room ... - Phys.Org - June 20th, 2017
- The Quantum Computer Factory That's Taking on Google and IBM - WIRED - June 20th, 2017
- Toward optical quantum computing - MIT News - June 17th, 2017
- Get ahead in quantum computing AND attract Goldman Sachs - eFinancialCareers - June 16th, 2017
- KPN CISO details Quantum computing attack dangers - Mobile World Live - June 16th, 2017
- Quantum Computing Technologies markets will reach $10.7 billion by 2024 - PR Newswire (press release) - June 14th, 2017
- From the Abacus to Supercomputers to Quantum Computers - Duke Today - June 13th, 2017
- Quantum Computers Will Analyze Every Financial Model at Once - Singularity Hub - June 13th, 2017
- Are Enterprises Ready to Take a Quantum Leap? - IT Business Edge - June 13th, 2017
- Scientists May Have Found a Way to Combat Quantum Computer Blockchain Hacking - Futurism - June 13th, 2017
- Microsoft and Purdue work on scalable topological quantum computer - Next Big Future - June 13th, 2017
- Doped Diamonds Push Practical Quantum Computing Closer to Reality - Motherboard - June 3rd, 2017
- Team develops first blockchain that can't be hacked by quantum computer - Siliconrepublic.com - June 3rd, 2017
- D-Wave partners with U of T to move quantum computing along - Financial Post - June 2nd, 2017
- Telstra just wants a quantum computer to offer as-a-service - ZDNet - June 1st, 2017
- Microsoft, Purdue Tackle Topological Quantum Computer - HPCwire - HPCwire (blog) - June 1st, 2017
- MIT Just Unveiled A Technique to Mass Produce Quantum Computers - Futurism - June 1st, 2017
- Here's How We Can Achieve Mass-Produced Quantum Computers - ScienceAlert - June 1st, 2017
- Research collaborative pursues advanced quantum computing - Phys.Org - June 1st, 2017
- AI and Quantum Computers Are Our Best Weapons Against Cyber Criminals - Futurism - June 1st, 2017
- Scientists claim to have invented the world's first quantum-proof ... - ScienceAlert - June 1st, 2017
- Google Plans to Demonstrate the Supremacy of Quantum ... - IEEE Spectrum - May 25th, 2017
- Top 5: Things to know about quantum computers - TechRepublic - May 25th, 2017
- Is the US falling behind in the race for quantum computing? - AroundtheO - May 25th, 2017
- Artificial intelligence and quantum computing aid cyber crime fight - Financial Times - May 25th, 2017