Establishing a detailed knowledge of the noise properties of superconducting systems is an important step towards the development of quantum computers, which will enable new types of computing.
However, the signals of these systems’ tiny electronic components, such as transistors on a chip, are so small that ambient noise creates interference. This problem is compounded by the delicate nature of the technology’s quantum physical states, which are also susceptible to noise.
Now, an international research team has successfully measured the noise spectrum of a superconducting circuit1—called a superconducting flux qubit—that is widely investigated for its potential in quantum computing applications.
Precise measurements of the environmental noise affecting superconducting flux qubits are important, according to team leader Jaw-Shen Tsai from the RIKEN Advanced Science Institute in Wako. “They may give us crucial information about the microscopic origin of the noise source, about which we have no solid understanding at all,” he says.
The superconducting flux qubit studied by the researchers is a circuit consisting of several junctions, and is a key technology in quantum computing because it can be integrated into a chip (Fig. 1). The first hurdle cleared by the researchers was keeping the qubit stable, and therefore viable, long enough to complete the measurement of the frequency spectrum of the noise that would occur in a quantum computer. They achieved this by applying a series of magnetic pulses that effectively replenished the qubit’s quantum state. The net effect of the magnetic pulses was to suppress detrimental contributions from low-frequency noise, as the pulses affect only the quantum states and not the noise.
Suppression of the low-frequency noise extended the lifetime of the quantum information in the qubit by almost an order of magnitude, and enabled the measurement of noise intensity in the system across three orders of magnitude in frequency from 0.2 to 20 MHz. This new-found knowledge on the noise spectrum will be valuable in developing strategies to counter such noise. “If we understand the nature of the noise, we may be able to reduce it considerably,” Tsai explains.
Moreover, the team’s strategy of extending qubit lifetimes to measure the noise spectrum is not limited to the study of quantum computing circuits; it could also be applied to other systems that operate under similar conditions. Medical imaging and sensing devices, for example, which often operate at the limits of signal resolution, could benefit from this noise reduction strategy.Reference
The corresponding author for this highlight is based at the Macroscopic Quantum Coherence Team, RIKEN Advanced Science Institute
Cutting edge research for the industries of tomorrow – DFKI and NICT expand cooperation
21.03.2017 | Deutsches Forschungszentrum für Künstliche Intelligenz GmbH, DFKI
Molecular motor-powered biocomputers
20.03.2017 | Technische Universität Dresden
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy