After running simulations at NERSC researchers believe it’s possible
Quantum computers have the potential to break common cryptography techniques, search huge datasets and simulate quantum systems in a fraction of the time it would take today’s computers. But before this can happen, engineers need to be able to harness the properties of quantum bits or qubits.
Currently, one of the leading methods for creating qubits in materials involves exploiting the structural atomic defects in diamond. But several researchers at the University of Chicago and Argonne National Laboratory believe that if an analogue defect could be engineered into a less expensive material, the cost of manufacturing quantum technologies could be significantly reduced. Using supercomputers at the National Energy Research Scientific Computing Center (NERSC), which is located at the Lawrence Berkeley National Laboratory (Berkeley Lab), these researchers have identified a possible candidate in aluminum nitride. Their findings were published in Nature Scientific Reports.
“Silicon semiconductors are reaching their physical limits—it’ll probably happen within the next five to 10 years—but if we can implement qubits into semiconductors, we will be able to move beyond silicon,” says Hosung Seo, University of Chicago Postdoctoral Researcher and a first author of the paper.
“Our community has been looking at diamond for some time, but it is interesting to study a less expensive material; our motivation is to find a practical and affordable replacement for silicon in semiconductors. Aluminum nitride is a perfect candidate because it is much cheaper than diamond and there are a number of technologies that can be developed starting from aluminum nitride wafers,” says Marco Govoni, Postdoctoral Researcher at the University of Chicago and Argonne National Laboratory. He is also a co-author of the paper.
In addition to Seo and Govoni, Giulia Galli is also a co-author on the paper. Galli is Liew Family Professor in Electronic Structure and Simulations at the University of Chicago’s Institute for Molecular Engineering.
The Strange World of Quantum Bits
Quantum mechanics describes the laws of nature on the scale of individual atoms, nuclei and electrons. At the quantum scale, physics gets strange. Take for example quantum entanglement: this occurs when pairs or groups of particles interact in such a way that the state of each particle cannot be described individually, instead the state must be described for the system as a whole. In other words, entangled particles act as a unit.
Another peculiar phenomenon of quantum mechanics is superposition, which occurs when two quantum states are added together to make another valid quantum state. So whereas a conventional computer bit encodes information as either zero or one, a qubit can be zero, one, or superposition of states (both zero and one at the same time). And, if these qubits could be linked or entangled in a quantum computer, problems that cannot be solved today with conventional computers could be tackled.
Today, one of the most promising solid-state qubits is created when a nitrogen atom occupies a place near a vacant site in a diamond’s carbon lattice; this defect is called a nitrogen-vacancy center in diamond. The presence of nitrogen is actually what gives the diamond its yellowish tint.
Using NERSC’s Edison supercomputer, the researchers found that by applying strain to aluminum nitride, one could create structural defects that may be harnessed as qubits similar to the one seen in diamond. Their calculations were performed using different levels of theory and the WEST code developed at the University of Chicago by Govoni, Galli and other researchers in Galli group.
“The WEST code allowed us to accurately predict the position of the defect levels in the band-gap of semiconductors,” says Seo. “Ideally, we want to have defect levels in the middle of the band-gap of materials because this means that that the defect’s electronic structure is well isolated from that of the host material. This is important for the qubit’s stability, to avoid de-coherence”
“We couldn’t have done this work without NERSC resources. In order to simulate these quantum defects you also need to accurately simulate the surrounding environment—this requires a lot of computational power,” says Govoni. “Basically you have a lot of atoms and a lot of electrons, and then in the middle of your simulation there is a defect which is the one you want to focus on, but it interacts with all the rest.”
The Latest on: Quantum Bits
via Google News
The Latest on: Quantum Bits
- The quest for quantum-proof encryption just made a leap forwardon August 3, 2020 at 2:22 am
Quantum computers could make encryption a thing of the past, but 15 contenders are trying to prove they have what it takes to safeguard your data.
- Quantum Computing: Why the technology poses a security threaton August 3, 2020 at 12:35 am
Amongst myriad potential benefits, Julian Hall explores how quantum computing is set to dramatically impact upon the security sector.
- Quantum Mechanics Proves 'Back to the Future' Is B.S.on August 1, 2020 at 6:50 am
They did this by running a quantum time travel simulation that runs backward and forward, letting them “damage” the past and see what resulted. And, as they say, the devil is in the details—the ...
- Quantum physicists say time travelers don’t have to worry about the butterfly effecton July 31, 2020 at 3:01 pm
What if I told you all your favorite time-travel films and books were actually created by big tech in order to wrest control of the time-travel industry from the proletariat? Think about it. Back to ...
- How to build a quantum workforceon July 30, 2020 at 11:34 am
Quantum computing requires an interdisciplinary approach and commitment to teach the principles at a young age, according to a panel of industry experts this week.
- Healing an Achilles' heel of quantum entanglementon July 30, 2020 at 9:27 am
Researchers have solved a 20-year-old problem in quantum information theory on how to calculate entanglement cost -- a way to measure entanglement -- in a manner that's efficiently computable, useful, ...
- Simulating quantum 'time travel' disproves butterfly effect in quantum realmon July 29, 2020 at 6:31 pm
Using a quantum computer to simulate time travel, researchers have demonstrated that, in the quantum realm, there is no 'butterfly effect.' In the research, information--qubits, or quantum bits--'time ...
- 'Giant atoms' enable quantum processing and communication in oneon July 29, 2020 at 8:02 am
MIT researchers have introduced a quantum computing architecture that can perform low-error quantum computations while also rapidly sharing quantum information between processors. The work represents ...
- U.S. hatches plan to build a quantum Internet that might be unhackableon July 24, 2020 at 12:33 pm
U.S. officials and scientists called building a quantum Internet one of the most important technological frontiers of the 21st century.
- How the Bits of Quantum Gravity Can Buzzon July 23, 2020 at 8:37 am
These hypothetical elementary particles are a cornerstone of theories of quantum gravity, which seek to unify Albert Einstein’s general theory of relativity with quantum mechanics. But they are ...
via Bing News