The researchers showed that they could detect the quantum correlations in the results of measurements of entangled quantum bits, using a superconducting electrical circuit.
The correlations are stronger than can be obtained using classical (non-quantum mechanical) physics, and according to the physicists, this illustrates that the oddities of quantum mechanics clearly extend to macroscopic systems. The work is part of an ongoing collaboration between the UCSB laboratories of John Martinis and Andrew Cleland.
The results of measurements in quantum mechanics are intrinsically unpredictable, according to the theory of quantum mechanics, and yet still contain very strong correlations, in contradiction with classical physics. In particular, measurements of "entangled states," such as a pair of particles with opposite spins, allow stringent tests of the predicted discrepancy between quantum and classical physics, as described by the "Bell inequalities." Measuring such a discrepancy is known as a "Bell violation."
According to quantum theory, Bell violations should be detectable using "qubits," superconducting quantum bits, but measuring these violations is technologically challenging. Martinis, Cleland, and their colleagues have overcome these challenges, and report a clear violation of Bell's inequality with two entangled superconducting qubits. Thus, they have demonstrated that this macroscopic electrical circuit is a quantum system.
The measurement of a Bell violation in a superconducting circuit was recently stated to be the next primary challenge for the superconducting qubit community, according to Martinis.
Martinis said: "This experiment has met this challenge, achieved by performing a very demanding measurement on a pair of Josephson qubits, a measurement that requires excellent control over qubit state preparation, qubit entanglement, and very high fidelity single-shot state measurements of the entangled qubits. It directly proves that quantum mechanics is the only possible description for the behavior of a macroscopic electrical circuit."
Additional co-authors on the paper (all at UCSB at the time of the research) are: Markus Ansmann, Haohua Wang, Radoslaw C. Biaalczak, Max Hofheinz, Erik Lucero, Matthew Neeley, Aaron D. O'Connell, Daniel Sank, Martin Weides, and James Wenner.
Gail Gallessich | EurekAlert!
Climate cycles may explain how running water carved Mars' surface features
02.12.2016 | Penn State
What do Netflix, Google and planetary systems have in common?
02.12.2016 | University of Toronto
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy