(Press-News.org) The promise of a quantum internet depends on the complexities of harnessing light to transmit quantum information over fiber optic networks. A potential step forward was reported today by researchers in Sweden who developed integrated chips that can generate light particles on demand and without the need for extreme refrigeration.
Quantum computing today relies on states of matter, that is, electrons which carry qubits of information to perform multiple calculations simultaneously, in a fraction of the time it takes with classical computing.
The co-author of the research, Val Zwiller, Professor at KTH Royal Institute of Technology, says that in order to integrate quantum computing seamlessly with fiber-optic networks--which are used by the internet today--a more promising approach would be to harness optical photons.
"The photonic approach offers a natural link between communication and computation," he says. "That's important, since the end goal is to transmit the processed quantum information using light."
But in order for photons to deliver qubits on-demand in quantum systems, they need to be emitted in a deterministic, rather than probabilistic, fashion. This can be accomplished at extremely low temperatures in artificial atoms, but today the research group at KTH reported a way to make it work in optical integrated circuits--at room temperature.
The new method enables photon emitters to be precisely positioned in integrated optical circuits that resemble copper wires for electricity, except that they carry light instead, says co-author of the research, Ali Elshaari, Associate Professor at KTH Royal Institute of Technology.
The researchers harnessed the single-photon-emitting properties of hexagonal boron nitride (hBN), a layered material. hBN is a compound commonly used is used ceramics, alloys, resins, plastics and rubbers to give them self-lubricating properties. They integrated the material with silicon nitride waveguides to direct the emitted photons.
Quantum circuits with light are either operated at cryogenic temperatures--plus 4 Kelvin above absolute zero--using atom-like single photon sources, or at room temperature using random single photon sources, Elshaari says. By contrast, the technique developed at KTH enables optical circuits with on-demand emission of light particles at room temperature.
"In existing optical circuits operating at room temperature, you never know when the single photon is generated unless you do a heralding measurement," Elshaari says. "We realized a deterministic process that precisely positions light-particles emitters operating at room temperature in an integrated photonic circuit."
The researchers reported coupling of hBN single photon emitter to silicon nitride waveguides, and they developed a method to image the quantum emitters. Then in a hybrid approach, the team built the photonic circuits with respect to the quantum sources locations using a series of steps involving electron beam lithography and etching, while still preserving the high quality nature of the quantum light.
The achievement opens a path to hybrid integration, that is, incorporating atom-like single-photon emitters into photonic platforms that cannot emit light efficiently on demand.
INFORMATION:
Cerebral aneurysms are malformations caused by abnormalities on the walls of blood vessels in the brain. When these blood vessels rupture, about 30% of the sufferers die on the spot, giving these the rightful label of 'ticking bombs in the head'. Recently, a research team at POSTECH has come up with a new treatment that can disassemble these time bombs by filling the aneurysm in blood with a new method.
In order to overcome the shortcomings of coil embolization, POSTECH's joint research team (Professor Joonwon Kim and Dr. Jongkyeong Lim of the Department of Mechanical Engineering with Professor ...
The skin, which covers the surface of the human body, is its largest organ. It is the first organ to show changes stemming from organ or physiological activity. It is especially common for diabetic patients to suffer from skin diseases or infections. Recently, a POSTECH research team has succeeded in creating a 3D artificial skin that enables observation of skin diseases of diabetic patients.
A research team led by Professor Dong-Woo Cho and Minjun Ahn of POSTECH's Department of Mechanical Engineering and Professor Byoung Soo Kim of School of Biomedical Convergence Engineering at Pusan National University has ...
A decade already passed from the first use of bioresorbable vascular scaffold in percutaneous coronary interventions. The first studies - by using surrogate endpoints - showed some superiority of BRS vs. metallic drug-eluting stent in terms of the so-called vascular restoration therapy with recovery of vasomotion and vascular pulsatility when the scaffold was absorbed.
Nevertheless, after these first promising findings, larger and randomized clinical trials and subsequent meta-analyses, powered to hard clinical endpoints, showed that bioresorbable vascular scaffolds, made ...
Researchers at KU Leuven (Belgium) have developed a 3D printing technique that extends the possibilities of lateral flow testing. These tests are widespread in the form of the classic pregnancy test and the COVID-19 self-tests. With the new printing technique, advanced diagnostic tests can be produced that are quick, cheap, and easy to use.
The COVID-19 pandemic has made everyone aware of the importance of rapid diagnosis. The sale of self-tests in pharmacies has been permitted in Belgium since the end of March. This self-test is a so-called lateral flow test. Using a ...
Analysis of The Autopsy, Toxicological, and Psychiatric Reports of Portugal's First Major Forensic Case: Part III
https://doi.org/10.1080/20961790.2021.1898079
Announcing a new article publication for Forensic Sciences Research journal. In this review article the author Ricardo Jorge Dinis-Oliveira of the University Institute of Health Sciences (IUCS)-CESPU, Gandra, Portugal continues a three-part investigation of the "Crime of Flores Street" one of the most famous cases of poisoning which occurred in Portugal in the late 19th century. The case demonstrated the weaknesses of the Portuguese medicolegal system and attests to the importance of toxicological analysis. The first article ...
Most people who are infected with SARS-CoV-2 develop no or only mild symptoms. However, some patients suffer severe life-threatening cases of COVID-19 and require intensive medical care and a ventilator to help them breathe. Many of these patients eventually succumb to the disease or suffer significant long-term health consequences. To identify and treat these patients at an early stage, a kind of "measuring stick" is needed - predictive biomarkers that can recognize those who are at risk of developing severe COVID-19.
First biomarker to predict severity of disease
A team led by Professor Burkhard Becher at the Institute of Experimental Immunology at the University of Zurich, working with researchers from Tübingen, Toulouse and Nantes, has now discovered such ...
Due to the chaotic nature of the atmosphere, weather forecasts, even with ever improving numerical weather prediction models, eventually lose all skill. Meteorologists have a strong desire to better understand this process as they try to trace forecast error back to observational gaps and to provide a means for improvement.
Root mean square error (rms, or its square, the variance distance) is often used to measure differences between simulated and observed fields. In this case, scientists measured the distance between a model forecast field within its grid and the verifying analysis field ...
A pioneering study by UCL scientists has discovered the presence of a harmful inflammatory protein in patients with symptomatic tuberculosis (TB).
Researchers say, by targeting the IL-17 cytokine, a component produced naturally by the immune system in response to infection, excessive and damaging lung inflammation caused by TB may be significantly reduced to help speed up patient recovery.
TB is an infection caused by the bacterium Mycobacterium tuberculosis and is the leading cause of death from infections worldwide. The World Health Organisation estimates that 1.4 million people died of TB disease worldwide in 2019.
Explaining the experimental study, lead author Dr Gabriele Pollara (UCL Division of Infection & Immunity), ...
In a time of a global crisis such as the ongoing COVID-19 pandemic, it is easy to note how people move through different phases to buckle up for such unprecedented and arduous times.
In the very beginning of the pandemic last year, we observed "an epidemic of fear", where it was all about the calamitous nature of a totally unknown virus and its worrying contagiousness and mortality rate. A few months later, with lockdown and restrictions already in place across the world, the fear was replaced by "an epidemic of explanations", where people even in their naivety, started to seek a sense of comfort by ...
Climate change, a pandemic or the coordinated activity of neurons in the brain: In all of these examples, a transition takes place at a certain point from the base state to a new state. Researchers at the Technical University of Munich (TUM) have discovered a universal mathematical structure at these so-called tipping points. It creates the basis for a better understanding of the behavior of networked systems.
It is an essential question for scientists in every field: How can we predict and influence changes in a networked system? "In biology, one example is the modelling of coordinated neuron activity," says Christian Kühn, professor of multiscale and stochastic dynamics ...
