Lifeboat Foundation

Conventional light sources for fiber-optic telecommunications emit many photons at the same time. Photons are particles of light that move as waves. In today €™s telecommunication networks, information is transmitted by modulating the properties of light waves traveling in optical fibers, similar to how radio waves are modulated in AM and FM channels.

In quantum communication, however, information is encoded in the phase of a single photon – the photon €™s position in the wave in which it travels. This makes it possible to connect quantum sensors in a network spanning great distances and to connect quantum computers together.

Researchers recently produced single-photon sources with operating wavelengths compatible with existing fiber communication networks. They did so by placing molybdenum ditelluride semiconductor layers just atoms thick on top of an array of nano-size pillars (Nature Communications, “Site-Controlled Telecom-Wavelength Single-Photon Emitters in Atomically-thin MoTe 2 ”).

Axions that decay into photons could account for visible light that exceeds what’s expected to come from all known galaxies.

If you could switch off the Milky Way’s stars and gaze at the sky with a powerful telescope, you’d see the cosmic optical background (COB)—visible-wavelength light emitted by everything outside our Galaxy. Recent studies by the New Horizons spacecraft—which, after its Pluto flyby, has been looking further afield—have returned the most precise measurements of the COB yet, showing it to be brighter than expected by a factor of 2. José Bernal and his colleagues at Johns Hopkins University in Maryland propose that this excess could be caused by decaying dark matter particles called axions [1]. They say that their model could be falsified or supported by future observations.

Comparing COB measurements to predictions provides a tool for testing hypotheses about the structure of the Universe. But measuring the COB is very difficult due to contamination by diffuse light from much nearer sources, especially sunlight scattered by interplanetary dust. Observing from the edge of our Solar System, New Horizons should be unaffected by most of this contamination, making the measured excess brightness a tool for improving our understanding of galaxy evolution.

So-called relativistic jets of energetic particles are stunning, destructive spectacles, and this one was “unprecedented.”

Water that simply will not freeze, no matter how cold it gets—a research group involving the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) has discovered a quantum state that could be described in this way.

Experts from the Institute of Solid State Physics at the University of Tokyo in Japan, Johns Hopkins University in the United States, and the Max Planck Institute for the Physics of Complex Systems (MPI-PKS) in Dresden, Germany, managed to cool a special material to near absolute zero temperature.

They found that a central property of atoms—their alignment—did not “freeze,” as usual, but remained in a “liquid” state. The new quantum material could serve as a model system to develop novel, highly sensitive quantum sensors. The team has presented its findings in the journal Nature Physics.

Massachusetts Institute of Technology (MIT) researchers are building swarms of tiny robots that have built-in intelligence, allowing them to build structures, vehicles, or even larger versions of themselves.

The subunit of the robot, which is being developed at MIT’s Center for Bits and Atoms, is called a voxel and is capable of carrying power and data.

“When we’re building these structures, you have to build in intelligence,” MIT Professor and CBA Director Neil Gershenfeld said in a statement. “What emerged was the idea of structural electronics — of making voxels that transmit power and data as well as force.”

IT WAS March 2018. The atmosphere at the annual meeting of the American Physical Society at the Los Angeles Convention Center was highly charged. The session had been moved to the atrium to accommodate the crowds, but people still had to cram onto the balconies to get a view of the action.

Rumours had it that Pablo Jarillo-Herrero, a physicist at the Massachusetts Institute of Technology, had something momentous to report. He and his colleagues had been experimenting with graphene, sheets of carbon just a single atom thick that are peeled from the graphite found in pencil lead. Graphene was already celebrated for its various promising electronic properties, and much more besides.

Here, Jarillo-Herrero showed that if you stacked two graphene sheets and twisted, or rotated, one relative to the other at certain “magic angles”, you could make the material an insulator, where electric current barely flows, or a superconductor, where current flows with zero resistance. It was a staggering trick, and potentially hugely significant because superconductivity holds promise for applications ranging from quantum computing to nuclear fusion.

Bohr’s model of the atom is kind of crazy. His collage of ideas mixing old and new concepts was the fruit of Bohr’s amazing intuition. Looking only at hydrogen, the simplest of all atoms, Bohr formed the image of a miniature solar system, with a proton in the center and the electron circling around it.

Following the physicist’s way of doing things, he wanted to explain some of his observed data with the simplest possible model. But there was a problem. The electron, being negatively charged, is attracted to the proton, which is positive. According to classical electromagnetism, the theory that describes how charged particles attract and repel one another, an electron would spiral down to the nucleus. As it circled the proton, it would radiate away its energy and fall in. No orbit would be stable, and atoms could not exist. Clearly, something new and revolutionary was needed. The solar system could only go so far as an analogy.

To salvage the atom, Bohr had to invent new rules that clashed with classical physics. He bravely suggested the implausible: What if the electron could only circle the nucleus in certain orbits, separated from each other in space like the steps of a ladder or the layers of an onion? Just like you can’t stand between steps, the electron can’t stay anywhere between two orbits. It can only jump from one orbit to another, the same way we can jump between steps. Bohr had just described quantum jumps.

Physicists at Google Quantum AI have used their quantum computer to study a type of effective particle that is more resilient to environmental disturbances that can degrade quantum calculations. These effective particles, known as Majorana edge modes, form as a result of a collective excitation of multiple individual particles, like ocean waves form from the collective motions of water molecules. Majorana edge modes are of particular interest in quantum computing applications because they exhibit special symmetries that can protect the otherwise fragile quantum states from noise in the environment.

The condensed matter physicist Philip Anderson once wrote, “It is only slightly overstating the case to say that physics is the study of symmetry.” Indeed, studying physical phenomena and their relationship to underlying symmetries has been the main thrust of physics for centuries. Symmetries are simply statements about what transformations a system can undergo—such as a translation, rotation, or inversion through a mirror—and remain unchanged. They can simplify problems and elucidate underlying physical laws. And, as shown in the new research, symmetries can even prevent the seemingly inexorable quantum process of decoherence.

When running a calculation on a quantum computer, we typically want the quantum bits, or “qubits,” in the computer to be in a single, pure quantum state. But decoherence occurs when external electric fields or other environmental noise disturb these states by jumbling them up with other states to create undesirable states. If a state has a certain symmetry, then it could be possible to isolate it, effectively creating an island of stability that is impossible to mix with the other states that don’t also have the special symmetry. In this way, since the noise can no longer connect the symmetric state to the others, it could preserve the coherence of the state.

Year 2021 😁

Spacecrafts in dozens of sci-fi movies like Star Trek use antimatter propulsion systems to travel at unimaginably high speeds by warping spacetime. By using them, traveling to different planets and stars is significantly more efficient and quick. However, is it possible to make this sci-fi idea a reality? If so, how and when will we be able to use them? Let’s take a closer look.

Continue reading “Antimatter Spacecraft: The Future of Interstellar Travel” »