Lifeboat Foundation

Superconducting circuits, which have zero electrical resistance, could enable the development of electronic components that are significantly more energy-efficient than most chips used today. Importantly, superconducting circuits rely on an electronic element known as the Josephson junction, which allows them to manipulate quantum information and mediate photon interactions. While past studies have tried to enhance the performance and coherence of Josephson circuits, so far, the most promising results in terms of photon lifetimes were achieved in microwave cavities.

A team of researchers at Princeton University, Northwestern University and the University of Chicago have directly operated an oscillator using a stimulated Josephson nonlinearity. In their paper, published in Nature Physics, the team achieved quantum control of an oscillator by operating it as an isolated two-level system, tailoring its Hilbert space.

“Our research was motivated by the ongoing effort in the superconducting circuits community to engineer highly coherent qubits for quantum information,” Prof. Andrew Houck, one of the researchers who carried out the study, told Phys.org. “There has been enormous progress in designing linear microwave resonators that can outperform the coherence of conventional superconducting qubits.”

Entropy is the physicist’s magic word, invoked to answer to some of the biggest questions in cosmology. Yet a quantum rethink may be needed to tell us what it actually is.

Amazon Web Services is offering access to quantum computers so developers can tinker around.

Physicists find hints that entanglement explains Einstein’s equations for gravity.

What – one vast, ancient and mysterious universe isn’t enough for you? Well, as it happens, there are others. Among physicists, it’s not controversial. Our universe is but one in an unimaginably massive ocean of universes called the multiverse.

If that concept isn’t enough to get your head around, physics describes different kinds of multiverse. The easiest one to comprehend is called the cosmological multiverse. The idea here is that the universe expanded at a mind-boggling speed in the fraction of a second after the big bang. During this period of inflation, there were quantum fluctuations which caused separate bubble universes to pop into existence and themselves start inflating and blowing bubbles. Russian physicist Andrei Linde came up with this concept, which suggests an infinity of universes no longer in any causal connection with one another – so free to develop in different ways.

Cosmic space is big – perhaps infinitely so. Travel far enough and some theories suggest you’d meet your cosmic twin – a copy of you living in a copy of our world, but in a different part of the multiverse. String theory, which is a notoriously theoretical explanation of reality, predicts a frankly meaninglessly large number of universes, maybe 10 to the 500 or more, all with slightly different physical parameters.

An intelligence startup warns that China is exploiting Western quantum scientists for military ends. The evidence is thin, but tensions are rising.

Determining the quantum mechanical behavior of many interacting particles is essential to solving important problems in a variety of scientific fields, including physics, chemistry and mathematics. For instance, in order to describe the electronic structure of materials and molecules, researchers first need to find the ground, excited and thermal states of the Born-Oppenheimer Hamiltonian approximation. In quantum chemistry, the Born-Oppenheimer approximation is the assumption that electronic and nuclear motions in molecules can be separated.

A variety of other scientific problems also require the accurate computation of Hamiltonian ground, excited and thermal states on a quantum computer. An important example are combinatorial optimization problems, which can be reduced to finding the ground state of suitable spin systems.

So far, techniques for computing Hamiltonian eigenstates on quantum computers have been primarily based on phase estimation or variational algorithms, which are designed to approximate the lowest energy eigenstate (i.e., ground state) and a number of excited states. Unfortunately, these techniques can have significant disadvantages, which make them impracticable for solving many scientific problems.

A team at Samsung Advanced Institute of Technology has announced that they have improved quantum dot (QD) technology for use in large displays by developing QDs that are both more efficient and have no heavy metals. In their paper published in the journal Nature, the group describes their work and their plans for the future. Alexander Efros, with the Naval Research Laboratory, in Washington D.C. has published a companion piece in the same journal issue outlining the work by the team at Samsung.

Quantum dots are nanoscale semiconducting crystals that have unique optical and electronic properties due to quirks of quantum mechanics. Since their development in the 1980s, scientists have been finding many uses for them in optical devices. Unfortunately, as Efros notes, they suffer from two problems that have prevented them from being fully utilized. The first is that they are based on cadmium, a toxic heavy metal. The second is the QD phosphors that are used in display devices—they are not self- emissive, which means they need to be replaced by QD light-emitting diodes in order for them to be competitively efficient. Notably current Samsung QLED TV screens do not use the QLEDs as a source of light—instead, LCDs produce backlight which is then absorbed by a film of quantum dots. In this new effort, the group at Samsung has made progress towards addressing both problems.

Forget Copenhagen, Many-Worlds, Pilot Waves and all the others. What you’re left with is reality.