Future quantum technologies may exploit identical particle entanglement

15.06. 2018 Quantum Physics News

Usually when physicists perform quantum entanglement between particles—whether it be qubits, atoms, photons, electrons, etc.—the particles are distinguishable in some way. Only recently have physicists demonstrated the feasibility of generating entanglement between particles that are completely identical. Interestingly, this entanglement exists just because of the indistinguishability of the particles, without any interaction between them.

Quantum transfer at the push of a button

15.06. 2018 Quantum Physics News

In new quantum information technologies, fragile quantum states have to be transferred between distant quantum bits. Researchers at ETH have now realized such a quantum transmission between two solid-state qubits at the push of a button.

Tracking down the mystery of entangled particles of light

14.06. 2018 Quantum Physics News

Bernese researchers have taken an important step towards new measurement methods such as quantum spectroscopy. In an experiment, they succeeded in uncovering part of the mystery surrounding the so-called "entangled photons" and gaining fine control on the measured correlations.

Harmonic oscillator’s most ‘classical-like’ state exhibits nonclassical behavior

14.06. 2018 Quantum Physics News

Showing just how blurry the boundary is between the quantum and classical worlds, physicists in a new study have theoretically demonstrated that a macroscopic oscillating object initially in a classical-like coherent state can exhibit nonclassical behavior—namely, it can violate the classical notion of realism by not having a single definite state at any given moment. Instead, the oscillator has one of two states with a certain probability, as theoretically shown by non-invasive measurements of the oscillator's position at different times.

Scientists make first ‘on demand’ entanglement link

13.06. 2018 Quantum Physics News

Researchers at QuTech in Delft have succeeded in generating quantum entanglement between two quantum chips faster than the entanglement is lost. Via a novel smart entanglement protocol and careful protection of the entanglement, the scientists led by Prof. Ronald Hanson are the first in the world to deliver such a quantum link on demand. This opens the door to connect multiple quantum nodes and create the very first quantum network in the world. Their results are published in Nature.

In physics, a famous paradox that hangs by a thread of light

13.06. 2018 Quantum Physics News

Imagine a metal bar that has been heated at one end. Instead of the heat gradually spreading over its entire length, the bar eventually becomes hot again at the place where it was originally. The fact that, paradoxically, a complex system returns to its original state instead of evolving toward equilibrium has drawn the attention of physicists for more than 60 years. Thanks to a series of advances in optical fibres, much richer and complete than before, our French-Italian team of researchers has just taken a crucial step in better understanding this phenomenon.

Quantum LEGO—building ultracold molecules

12.06. 2018 Quantum Physics News

Cooling matter is not easy. Atoms and molecules have the tendency to jump around, to rotate and to vibrate. Freezing these particles by slowing them down is a complicated process. For individual atoms, physicists have figured out over the years how to carry out this cooling process, using techniques like laser cooling, where finely tuned lasers remove energy from the particles. Molecules, on the other hand, are much harder to cool down so that they stand still. These particles consist of two or more atoms that are bound together, and as compound particles they are able to jiggle around in many more ways.

Boson sampling with photons found to produce useful output in spite of photon leaks for quantum supremacy

11.06. 2018 Quantum Physics News

A team of researchers from China, Germany and the U.S. has found that boson sampling with photons is a viable option for testing for quantum supremacy, despite photons leaking from a given test system. In their paper published in the journal Physical Review Letters, the group describes testing the idea using photons emitted from a quantum dot.

Silicon provides means to control quantum bits for faster algorithms

08.06. 2018 Quantum Physics News

Quantum bits are now easier to manipulate for devices in quantum computing, thanks to enhanced spin-orbit interaction in silicon.

Researchers find evidence suggesting spin liquids in ferromagnets may be similar to dipole liquids in ferroelectrics

08.06. 2018 Quantum Physics News

A team of researchers with members from several institutions in the U.S. and Russia has found evidence that suggests spin liquids in ferromagnets may be similar to dipole liquids in ferroelectrics. In their paper published in the journal Science, the group describes their study of molecular crystals and what they found. Ben Powell with the University of Queensland offers a Perspective piece on the work done by the team in the same journal issue.

Seeing the light? Study illuminates how quantum magnets mimic light

06.06. 2018 Quantum Physics News

What is light? It sounds like a simple question, but it is one that has occupied some of the best scientific minds for centuries.

Transferring quantum information using sound

06.06. 2018 Quantum Physics News

Quantum physics has led to new types of sensors, secure data transmission methods and researchers are working toward computers. However, the main obstacle is finding the right way to couple and precisely control a sufficient number of quantum systems (for example, individual atoms).

Quantum stopwatch stores time in a quantum memory

05.06. 2018 Quantum Physics News

Physicists have developed a "quantum stopwatch"—a method that stores time (in the form of states of quantum clocks) in a quantum memory. In doing so, the method avoids the accumulation of errors that usually occurs when measuring the duration of a sequence of events. In this way, the quantum stopwatch increases the accuracy of measuring time at the quantum level, which is essential for applications such as GPS, astronomy research, and distributed computing.

Detecting the birth and death of a phonon

05.06. 2018 Quantum Physics News

Phonons are discrete units of vibrational energy predicted by quantum mechanics that correspond to collective oscillations of atoms inside a molecule or a crystal. When such vibrations are produced by light interacting with a material, the vibrational energy can be transferred back and forth between individual phonons and individual packets of light energy, the photons. This process is called the Raman effect.

NIST atomic clock comparison confirms key assumptions of ‘Einstein’s elevator’

04.06. 2018 Quantum Physics News

By comparing different types of remote atomic clocks, physicists at the National Institute of Standards and Technology (NIST) have performed the most accurate test ever of a key principle underlying Albert Einstein's famous theory of general relativity, which describes how gravity relates to space and time.