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More insights around the logical quantum gate for photons discovered by Max Planck Institute of Quantum Optics (MPQ). Being able to leverage this gate enables Qubits in transmission and processing can be more controlled and manipulated through this discovery, and places us closer to a stable Quantum Computing environment.


MPQ scientists take an important step towards a logical quantum gate for photons.

Scientists from all over the world are working on concepts for future quantum computers and their experimental realization. Commonly, a typical quantum computer is considered to be based on a network of quantum particles that serve for storing, encoding and processing quantum information. In analogy to the case of a classical computer a quantum logic gate that assigns output signals to input signals in a deterministic way would be an essential building block. A team around Dr. Stephan Dürr from the Quantum Dynamics Division of Prof. Gerhard Rempe at the Max Planck Institute of Quantum Optics has now demonstrated in an experiment how an important gate operation — the exchange of the binary bit values 0 and 1 — can be realized with single photons. A first light pulse containing one photon only is stored as an excitation in an ultracold cloud of about 100,000 rubidium atoms.

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Predictions from quantum physics have been confirmed by countless experiments, but no one has yet detected the quantum physical effect of entanglement directly with the naked eye. This should now be possible thanks to an experiment proposed by a team around a theoretical physicist at the University of Basel. The experiment might pave the way for new applications in quantum physics.

Quantum physics is more than 100 years old, but even today is still sometimes met with wonderment. This applies, for example, to entanglement, a quantum physical phenomenon that can be observed between atoms or photons (light particles): when two of these particles are entangled, the physical state of the two particles can no longer be described independently, only the total system that both particles form together.

Despite this peculiarity, entangled photons are part of the real world, as has been proven in many experiments. And yet no one has observed entangled photons directly. This is because only single or a handful of entangled photons can be produced with the available technology, and this number is too low for the to perceive these photons as light.

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One of the longest standing mysteries of black holes is what happens to stuff when it falls inside. Information can’t move faster than light, so it can’t escape a black hole, but we know that black holes shrink and evaporate over time, emitting Hawking radiation. This has troubled scientists for 40 years. Information can’t simply vanish.

Now, physicists Kamil Brádler and Chris Adami, from the University of Ottawa and Michigan State University respectively, have been able to show that the information is not at all lost, but is transferred from the black holes into the aforementioned Hawking radiation, potentially solving a long-standing mystery of cosmology.

Over 40 years ago, Stephen Hawking put forward the idea that although nothing can escape a black hole, there should be a certain amount of particles emitted from the outer edge of the black hole’s event horizon. This emission would over time steal energy from a black hole, causing it to evaporate and shrink.

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Physicists may soon know if a potential new subatomic particle is something beyond their wildest dreams — or if it exists at all.

Hints of the new particle emerged last December at the Large Hadron Collider. Theorists have churned out hundreds of papers attempting to explain the existence of the particle —assuming it’s not a statistical fluke. Scientists are now beginning to converge on the most likely explanations.

“If this thing is true, it’s huge. It’s very different than what the last 30 years of particle physics looked like,” says theoretical physicist David Kaplan of Johns Hopkins University.

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RPI’s new material takes semiconducting transistors to new levels.


Two-dimensional phosphane, a material known as phosphorene, has potential application as a material for semiconducting transistors in ever faster and more powerful computers. But there’s a hitch. Many of the useful properties of this material, like its ability to conduct electrons, are anisotropic, meaning they vary depending on the orientation of the crystal. Now, a team including researchers at Rensselaer Polytechnic Institute (RPI) has developed a new method to quickly and accurately determine that orientation using the interactions between light and electrons within phosphorene and other atoms-thick crystals of black phosphorus. Phosphorene—a single layer of phosphorous atoms—was isolated for the first time in 2014, allowing physicists to begin exploring its properties experimentally and theoretically. Vincent Meunier, head of the Rensselaer Department of Physics, Applied Physics, and Astronomy and a leader of the team that developed the new method, published his first paper on the material—confirming the structure of phosphorene—in that same year.

“This is a really interesting material because, depending on which direction you do things, you have completely different properties,” said Meunier, a member of the Rensselaer Center for Materials, Devices, and Integrated Systems (cMDIS). “But because it’s such a new material, it’s essential that we begin to understand and predict its intrinsic properties.”

Meunier and researchers at Rensselaer contributed to the theoretical modeling and prediction of the properties of phosphorene, drawing on the Rensselaer supercomputer, the Center for Computational Innovations (CCI), to perform calculations. Through the Rensselaer cMDIS, Meunier and his team are able to develop the potential of new materials such as phosphorene to serve in future generations of computers and other devices. Meunier’s research exemplifies the work being done at The New Polytechnic, addressing difficult and complex global challenges, the need for interdisciplinary and true collaboration, and the use of the latest tools and technologies, many of which are developed at Rensselaer.

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With apologies to Isaac Asimov, the most exciting phase to hear in science isn’t “Eureka,” but “That’s funny…”

A “that’s funny” moment in a Colorado State University physics lab has led to a fundamental discovery that could play a key role in next-generation microelectronics.

Publishing in Nature Physics April 25, the scientists, led by Professor of Physics Mingzhong Wu in CSU’s College of Natural Sciences, are the first to demonstrate using non-polarized light to produce in a metal what’s called a spin voltage — a unit of power produced from the quantum spinning of an individual electron. Controlling electron spins for use in memory and logic applications is a relatively new field called spin electronics, or spintronics, and the subject of the 2007 Nobel Prize in Physics.

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The concept is known as a “parallel universe,” and is a facet of the astronomical theory of the multiverse. There actually is quite a bit of evidence out there for a multiverse. First, it is useful to understand how our universe is believed to have come to be.

Around 13.7 billion years ago, simply speaking, everything we know of in the cosmos was an infinitesimal singularity. Then, according to the Big Bang theory, some unknown trigger caused it to expand and inflate in three-dimensional space. As the immense energy of this initial expansion cooled, light began to shine through. Eventually, the small particles began to form into the larger pieces of matter we know today, such as galaxies, stars and planets.

One big question with this theory is: are we the only universe out there. With our current technology, we are limited to observations within this universe because the universe is curved and we are inside the fishbowl, unable to see the outside of it (if there is an outside.)

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Ninety-five percent of the universe is still considered unexplored. Scientists at CERN, the world’s largest particle physics research center, located in Geneva, are working on solving these mysteries. In May 2012, researchers there discovered the so-called Higgs Boson, whose prediction won Peter Higgs and François Englert the Nobel prize in physics. One of the things CERN scientists are researching at the moment is dark matter: Although it may well have five times the mass of visible matter in the universe, this extent can only be indirectly proved. With a bit of luck, CERN will also succeed in generating dark matter.

A unique sensor chip can contribute to proving the existence of : It is eight inches or 15 cm x 10 cm and was developed jointly by Infineon Technologies Austria and the Austrian Academy of Sciences’ Institute of High Energy Physics (HEPHY). Tens of thousands of these silicon components could be used at CERN in the near future. They are not only more economical to produce than previous sensors, which measured up to six inches. The components also stand up better to constant radiation and thus age slower than the previous generation. Planned experiments will scarcely be possible without resistant sensors.

The experiments at CERN are analyzing the structure of matter and the interplay among elementary particles: Protons are accelerated almost to the speed of light and then made to collide, giving rise to new particles whose properties can be reconstructed with various detectors. “In and cosmology, there are many questions that are still open and to which mankind still has no answer,” says Dr. Manfred Krammer, head of the Experimental Physics Department at CERN. “To make new advances in these areas, we need a new generation of particle sensors. Cooperation with high-tech companies like Infineon allows us to develop the technologies we need for that.”

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