Deep in outer space, invisible hands mold the universe. One is dark matter, an unseen substance thought to bind distant galaxies. The other is dark energy, a force believed to push stellar structures apart with gravity-defying strength.
Researchers aiming to create a secure quantum version of the internet need a device called a quantum repeater, which doesn’t yet exist — but now two teams say they are well on the way to building one.
By Alex Wilkins
The desktop-sized LPU100 eschews traditional electronics and qubits in favor of lasers, and it can reportedly perform complex AI calculations in nanoseconds.
Close friend and coworker Thomas Hertog explores the groundbreaking physicist’s theories regarding the Big Bang’s beginnings on this, the sixth anniversary of Stephen Hawking’s passing.
I was appointed as Stephen Hawking’s PhD student in 1998 “to work on a quantum theory of the Big Bang.” Over the course of about 20 years, what began as a doctoral project evolved into a close collaboration that came to an end only six years ago, on March 14, 2018, when he passed away.
The mystery that drove our investigation during this time was how the Big Bang could have produced conditions that were so ideal for life. How should we interpret this enigmatic display of intent?
It’s one thing to dream up a quantum internet that could send hacker-proof information around the world via photons superimposed in different quantum states. It’s quite another to physically show it’s possible.
In its superconducting state, an exotic metal harbors charge carriers that appear to have 4 and 6 times the charge of a single electron, suggesting the formation of Cooper-pair “molecules.”
A kagome crystal features two-dimensional atomic layers whose structure resembles a traditional Japanese basket weave called kagome. For several decades, the kagome crystals that attracted the most attention were insulating magnets. The geometric frustration inherent in their kagome structure could, it was hoped, engender a much-sought exotic state known as a quantum spin liquid. By contrast, the metallic side of the kagome family was more of a theoretical curiosity. That status changed in 2019 with the discovery of exotic electronic behavior—Dirac fermions and flat bands—in the kagome metal FeSn [1]. A bigger surprise followed a year later when superconductivity was observed in the kagome metal cesium vanadium antimonide (CsV3Sb5, or CVS for short) [2].
The ability to store molecules in reconfigurable optical traps could allow researchers to harness the rich physics of molecules in quantum applications.
DARPA is funding the development of a military-grade quantum laser prototype that can penetrate dense fog and operate over long distances.
An “optical conveyor belt” that can move polaritons—a type of light-matter hybrid particle—in semiconductor-based microcavities.
This asymmetric response of the confined polaritons breaks time-reversal symmetry, driving non-reciprocity and the formation of a topological band structure.
Photonic states with topological properties can be used in advanced opto-electronic devices where topology might greatly improve the performance of optical devices, circuits, and networks, such as by reducing noise and lasing threshold powers, and dissipationless optical waveguiding.
Continue reading “Scientists create an ‘optical conveyor belt’ for quasiparticles” »
Using a clever laser technique, scientists have squished pairs of atoms closer together than ever before, revealing some truly mind-boggling quantum effects.
