Lifeboat Foundation

The efficient generation of entanglement between remote quantum nodes is a crucial step in securing quantum communications. In past research, entanglement has often been achieved using a number of different probabilistic schemes.

Recently, some studies have also offered demonstrations of deterministic remote entanglement using approaches based on superconducting qubits. Nonetheless, the deterministic violation of Bell’s inequality (a strong measure of quantum correlation) in a superconducting quantum communication architecture has so far never been demonstrated.

A team of researchers based at the University of Chicago has recently demonstrated a violation of Bell’s inequality using remotely connected superconducting qubits. Their paper, published in Nature Physics, introduces a simple and yet robust architecture for achieving this benchmark result in a superconducting system.

Continue reading “Researchers violate Bell’s inequality with remotely connected superconducting qubits” »

Matter waves constitute a crucial feature of quantum mechanics, in which particles have wave properties in addition to particle characteristics. This wave-particle duality was postulated in 1924 by the French physicist Louis de Broglie. The existence of the wave property of matter has been successfully demonstrated in a number of experiments with electrons and neutrons, as well as with more complex matter, up to large molecules.

For antimatter, the wave-particle duality has also been proven through diffraction experiments. However, researchers of the QUPLAS collaboration have now established wave behavior in a single positron (antiparticle to the electron) interference experiment. The results are reported in Science Advances.

The QUPLAS scientific collaboration includes researchers from the University of Bern and from the University and Politecnico of Milano. To demonstrate the wave duality of single positrons, they performed measurements with a setup similar to the so-called double-slit experiment. This setup was suggested by physicists including Albert Einstein and Richard Feynman; it is often used in quantum theory to demonstrate the wave nature of particles.

Continue reading “First demonstration of antimatter wave interferometry” »

A proposed experiment to swap fundamental properties between photons carries profound implications for our understanding of reality itself.

• By Anil Ananthaswamy on May 6, 2019

A photodetector converts light into an electrical signal, causing the light to be lost. Researchers led by Tracy Northup at the University of Innsbruck have now built a quantum sensor that can measure light particles non-destructively. It can be used to further investigate the quantum properties of light.

Physicist Tracy Northup is currently researching the development of quantum internet at the University of Innsbruck. The American citizen builds interfaces with which quantum information can be transferred from matter to light and vice versa. Over such interfaces, it is anticipated that quantum computers all over the world will be able to communicate with each other via fiber optic lines in the future. In their research, Northup and her team at the Department of Experimental Physics have now demonstrated a method with which visible light can be measured non-destructively. The development follows the work of Serge Haroche, who characterized the quantum properties of microwave fields with the help of neutral atoms in the 1990s and was awarded the Nobel Prize in Physics in 2012.

In work led by postdoc Moonjoo Lee and Ph.D. student Konstantin Friebe, the researchers place an ionized calcium atom between two hollow mirrors through which visible laser light is guided. “The ion has only a weak influence on the light,” explains Tracy Northup. “Quantum measurements of the ion allow us to make statistical predictions about the number of light particles in the chamber.” The physicists were supported in their interpretation of the measurement results by the research group led by Helmut Ritsch, a Innsbruck quantum optician from the Department of Theoretical Physics. “One can speak in this context of a quantum sensor for light particles”, sums up Northup, who has held an Ingeborg Hochmair professorship at the University of Innsbruck since 2017. One application of the new method would be to generate special tailored light fields by feeding the measurement results back into the system via a feedback loop, thus establishing the desired states.

Continue reading “Quantum sensor for photons” »

Quantum communication is a strange beast, but one of the weirdest proposed forms of it is called counterfactual communication — a type of quantum communication where no particles travel between two recipients.

Theoretical physicists have long proposed that such a form of communication would be possible, but in 2017, for the first time, researchers were able to experimentally achieve it — transferring a black and white bitmap image from one location to another without sending any physical particles.

Continue reading “Scientists Have Finally Achieved Direct Counterfactual Quantum Communication” »

Quantum physicist Paul Kwiat reveals what it takes do well in LabEscape, his science-themed escape room.

Circa 2016

Entanglement is an extremely strong correlation that can exist between quantum systems. These correlations are so strong that two or more entangled particles have to be described with reference to each other, even though the individual objects may be spatially separated.

Continue reading “Quantum Entanglement harvesting in a vacuum” »

Like memory in conventional computers, quantum memory components are essential for quantum computers—a new generation of data processors that exploit quantum mechanics and can overcome the limitations of classical computers. With their potent computational power, quantum computers may push the boundaries of fundamental science to create new drugs, explain cosmological mysteries, or enhance accuracy of forecasts and optimization plans. Quantum computers are expected to be much faster and more powerful than their traditional counterparts as information is calculated in qubits, which, unlike the bits used in classical computers, can represent both zero and one in a simultaneous superstate.

Photonic quantum memory allows for the storage and retrieval of flying single-photon quantum states. However, production of such highly efficient quantum memory remains a major challenge as it requires a perfectly matched photon-matter quantum interface. Meanwhile, the energy of a single photon is too weak and can be easily lost into the noisy sea of stray light background. For a long time, these problems suppressed quantum memory efficiencies to below 50 percent—a threshold value crucial for practical applications.

Now, for the first time, a joint research team led by Prof. Du Shengwang from HKUST, Prof. Zhang Shanchao from SCNU, Prof. Yan Hui from SCNU and Prof. Zhu Shi-Liang from SCNU and Nanjing University has found a way to boost the efficiency of photonic quantum memory to over 85 percent with a fidelity of over 99 percent.

Continue reading “Physicists set a new record of quantum memory efficiency” »

The future of VPNs may be fighting quanta with quanta.