Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New research brings scientists one step closer to a fully functioning quantum computer

26.09.2019

Quantum computing has the potential to revolutionize technology, medicine, and science by providing faster and more efficient processors, sensors, and communication devices.

But transferring information and correcting errors within a quantum system remains a challenge to making effective quantum computers.


John Nichol's research brings scientists one step closer to creating a fully functional quantum computer, a type of computer that operates on the principles of quantum mechanics. Seen here, a quantum processor semiconductor chip is connected to a circuit board. Thin aluminum wires are connected from the surface of the semiconductor chip to pads on the circuit board, which allows users to perform electrical control and readouts of the device by sending and receiving electrical signals during experiments. The researchers fabricate the device by patterning and depositing metal gates on a GaAs/AlGaAs heterostructure chip. The metal gates are designed to be able to trap individual electrons in the semiconductor. They send electrical signals down to the device and change the voltage on the metal gates to perform various controls of the electrons. They also receive electrical signals from the device to help monitor the electrons' behavior.

Credit: University of Rochester photo / J. Adam Fenster

In a paper in the journal Nature, researchers from Purdue University and the University of Rochester, including John Nichol, an assistant professor of physics, and Rochester PhD students Yadav P. Kandel and Haifeng Qiao, demonstrate their method of relaying information by transferring the state of electrons.

The research brings scientists one step closer to creating fully functional quantum computers and is the latest example of Rochester's initiative to better understand quantum behavior and develop novel quantum systems.

The University recently received a $4 million grant from the Department of Energy to explore quantum materials.

QUANTUM COMPUTERS

A quantum computer operates on the principles of quantum mechanics, a unique set of rules that govern at the extremely small scale of atoms and subatomic particles.

When dealing with particles at these scales, many of the rules that govern classical physics no longer apply and quantum effects emerge; a quantum computer is able to perform complex calculations, factor extremely large numbers, and simulate the behaviors of atoms and particles at levels that classical computers cannot.

Quantum computers have the potential to provide more insight into principles of physics and chemistry by simulating the behavior of matter at unusual conditions at the molecular level.

These simulations could be useful in developing new energy sources and studying the conditions of planets and galaxies or comparing compounds that could lead to new drug therapies.

"You and I are quantum systems. The particles in our body obey quantum physics. But, if you try to compute what happens with all of the atoms in our body, you cannot do it on a regular computer," Nichol says. "A quantum computer could easily do this."

Quantum computers could also open doors for faster database searches and cryptography.

"It turns out that almost all of modern cryptography is based on the extreme difficulty for regular computers to factor large numbers," Nichol says. "Quantum computers can easily factor large numbers and break encryption schemes, so you can imagine why lots of governments are interested in this."

BITS VS. QUBITS

A regular computer consists of billions of transistors, called bits. Quantum computers, on the other hand, are based on quantum bits, also known as qubits, which can be made from a single electron. Unlike ordinary transistors, which can be either "0" or "1," qubits can be both "0" and "1" at the same time.

The ability for individual qubits to occupy these "superposition states," where they are simultaneously in multiple states, underlies the great potential of quantum computers. Just like ordinary computers, however, quantum computers need a way to transfer information between qubits, and this presents a major experimental challenge.

"A quantum computer needs to have many qubits, and they're really difficult to make and operate," Nichol says. "The state-of-the art right now is doing something with only a few qubits, so we're still a long ways away from realizing the full potential of quantum computers."

All computers, including both regular and quantum computers and devices like smart phones, also have to perform error correction. A regular computer contains copies of bits so if one of the bits goes bad, "the rest are just going to take a majority vote" and fix the error. However, quantum bits cannot be copied, Nichol says, "so you have to be very clever about how you correct for errors. What we're doing here is one step in that direction."

MANIPULATING ELECTRONS

Quantum error correction requires that individual qubits interact with many other qubits. This can be difficult because an individual electron is like a bar magnet with a north pole and a south pole that can point either up or down. The direction of the pole--whether the north pole is pointing up or down, for instance--is known as the electron's magnetic moment or quantum state.

If certain kinds of particles have the same magnetic moment, they cannot be in the same place at the same time. That is, two electrons in the same quantum state cannot sit on top of each other.

"This is one of the main reasons something like a penny, which is made out of metal, doesn't collapse on itself," Nichol says. "The electrons are pushing themselves apart because they cannot be in the same place at the same time."

If two electrons are in opposite states, they can sit on top of each other. A surprising consequence of this is that if the electrons are close enough, their states will swap back and forth in time.

"If you have one electron that's up and another electron that's down and you push them together for just the right amount of time, they will swap," Nichol says. "They did not switch places, but their states switched."

To force this phenomenon, Nichol and his colleagues cooled down a semiconductor chip to extremely low temperatures. Using quantum dots--nanoscale semiconductors--they trapped four electrons in a row, then moved the electrons so they came in contact and their states switched.

"There's an easy way to switch the state between two neighboring electrons, but doing it over long distances--in our case, it's four electrons--requires a lot of control and technical skill," Nichol says. "Our research shows this is now a viable approach to send information over long distances."

A FIRST STEP

Transmitting the state of an electron back and forth across an array of qubits, without moving the position of electrons, provides a striking example of the possibilities allowed by quantum physics for information science.

"This experiment demonstrates that information in quantum states can be transferred without actually transferring the individual electron spins down the chain," says Michael Manfra, a professor of physics and astronomy at Purdue University. "It is an important step for showing how information can be transmitted quantum-mechanically--in manners quite different than our classical intuition would lead us to believe."

Nichol likens this to the steps that led from the first computing devices to today's computers. That said, will we all someday have quantum computers to replace our desktop computers? "If you had asked that question of IBM in the 1960s, they probably would've said no, there's no way that's going to happen," Nichol says. "That's my reaction now. But, who knows?"

Media Contact

Lindsey Valich
lvalich@ur.rochester.edu
585-276-6264

 @UofR

http://www.rochester.edu 

Lindsey Valich | EurekAlert!

More articles from Information Technology:

nachricht NIST-led team develops tiny low-energy device to rapidly reroute light in computer chips
14.11.2019 | National Institute of Standards and Technology (NIST)

nachricht Fraunhofer Radio Technology becomes part of the worldwide Telecom Infra Project (TIP)
14.11.2019 | Fraunhofer-Institut für Angewandte Informationstechnik FIT

All articles from Information Technology >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New opportunities in additive manufacturing presented

Fraunhofer IFAM Dresden demonstrates manufacturing of copper components

The Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM in Dresden has succeeded in using Selective Electron Beam Melting (SEBM) to...

Im Focus: New Pitt research finds carbon nanotubes show a love/hate relationship with water

Carbon nanotubes (CNTs) are valuable for a wide variety of applications. Made of graphene sheets rolled into tubes 10,000 times smaller than a human hair, CNTs have an exceptional strength-to-mass ratio and excellent thermal and electrical properties. These features make them ideal for a range of applications, including supercapacitors, interconnects, adhesives, particle trapping and structural color.

New research reveals even more potential for CNTs: as a coating, they can both repel and hold water in place, a useful property for applications like printing,...

Im Focus: Magnets for the second dimension

If you've ever tried to put several really strong, small cube magnets right next to each other on a magnetic board, you'll know that you just can't do it. What happens is that the magnets always arrange themselves in a column sticking out vertically from the magnetic board. Moreover, it's almost impossible to join several rows of these magnets together to form a flat surface. That's because magnets are dipolar. Equal poles repel each other, with the north pole of one magnet always attaching itself to the south pole of another and vice versa. This explains why they form a column with all the magnets aligned the same way.

Now, scientists at ETH Zurich have managed to create magnetic building blocks in the shape of cubes that - for the first time ever - can be joined together to...

Im Focus: A new quantum data classification protocol brings us nearer to a future 'quantum internet'

The algorithm represents a first step in the automated learning of quantum information networks

Quantum-based communication and computation technologies promise unprecedented applications, such as unconditionally secure communications, ultra-precise...

Im Focus: Distorted Atoms

In two experiments performed at the free-electron laser FLASH in Hamburg a cooperation led by physicists from the Heidelberg Max Planck Institute for Nuclear physics (MPIK) demonstrated strongly-driven nonlinear interaction of ultrashort extreme-ultraviolet (XUV) laser pulses with atoms and ions. The powerful excitation of an electron pair in helium was found to compete with the ultrafast decay, which temporarily may even lead to population inversion. Resonant transitions in doubly charged neon ions were shifted in energy, and observed by XUV-XUV pump-probe transient absorption spectroscopy.

An international team led by physicists from the MPIK reports on new results for efficient two-electron excitations in helium driven by strong and ultrashort...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

High entropy alloys for hot turbines and tireless metal-forming presses

05.11.2019 | Event News

Smart lasers open up new applications and are the “tool of choice” in digitalization

30.10.2019 | Event News

International Symposium on Functional Materials for Electrolysis, Fuel Cells and Metal-Air Batteries

02.10.2019 | Event News

 
Latest News

Theoretical tubulanes inspire ultrahard polymers

14.11.2019 | Materials Sciences

Can 'smart toilets' be the next health data wellspring?

14.11.2019 | Health and Medicine

New spin directions in pyrite an encouraging sign for future spintronics

14.11.2019 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>