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Category: quantum physics

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.

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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.

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Here’s a curious thought experiment. Imagine a cloud of quantum particles that are entangled—in other words, they share the same quantum existence. The behavior of these particles is chaotic. The goal of this experiment is to send a quantum message across this set of particles. So the message has to be sent into one side of the cloud and then extracted from the other.

The first step, then, is to divide the cloud down the middle so that the particles on the left can be controlled separately from those on the right. The next step is to inject the message into the left-hand part of the cloud, where the chaotic behavior of the particles quickly scrambles it.

Can such a message ever be unscrambled?

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A pair of physicists from Immanuel Kant Baltic Federal University (IKBFU) in Russia recently proposed an entirely new view of the cosmos. Their research takes the wacky idea that we’re living in a computer simulation and mashes it up with the mind-boggling “many worlds” theory to say that, essentially, our entire universe is part of an immeasurably large quantum system spanning “uncountable” multiverses.

When you think about quantum systems, like IBM and Google’s quantum computers, we usually imagine a device that’s designed to work with subatomic particles – qubits – to perform quantum calculations.

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The universe is governed by four fundamental forces: gravity, electromagnetism, and the strong and weak nuclear forces. These forces drive the motion and behavior of everything we see around us. At least that’s what we think. But over the past several years there’s been increasing evidence of a fifth fundamental force. New research hasn’t discovered this fifth force, but it does show that we still don’t fully understand these cosmic forces.

The fundamental forces are a part of the standard model of particle physics. This model describes all the various quantum particles we observe, such as electrons, protons, antimatter, and such. Quarks, neutrinos and the Higgs boson are all part of the model.

The term “force” in the model is a bit of a misnomer. In the standard model, each force is the result of a type of carrier boson. Photons are the carrier boson for electromagnetism. Gluons are the carrier bosons for the strong, and bosons known as W and Z are for the weak. Gravity isn’t technically part of the standard model, but it’s assumed that quantum gravity has a boson known as the graviton. We still don’t fully understand quantum gravity, but one idea is that gravity can be united with the standard model to produce a grand unified theory (GUT).

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O.,.,o I think we need sunglasses or optics to see ghosts or exterrestials using quantum mechanical physics.

Cameras on the International Space Station have reportedly captured images of soundwaves travelling across Earth at high speeds, believed by some people to be a new form of ‘space technology’.

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The quest to develop the understanding for time crystalline behaviour in quantum systems has taken a new, exciting twist.

Physics experts from the Universities of Exeter, Iceland, and ITMO University in St. Petersburg, have revealed that the existence of genuine time crystals for closed quantum systems is possible.

Different from other studies which to date considered non-equilibrium open quantum systems, where the presence of a drive induces time-periodic oscillations, researchers have theoretically found a quantum system where time correlations survive for an infinitely long time.

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An international team led by researchers at Princeton University has directly observed a surprising quantum effect in a high-temperature iron-containing superconductor.

Superconductors conduct electricity without resistance, making them valuable for long-distance electricity transmission and many other energy-saving applications. Conventional superconductors operate only at extremely low temperatures, but certain iron-based materials discovered roughly a decade ago can superconduct at relatively high temperatures and have drawn the attention of researchers.

Exactly how forms in iron-based materials is something of a mystery, especially since iron’s magnetism would seem to conflict with the emergence of superconductivity. A deeper understanding of unconventional materials such as iron-based superconductors could lead eventually to new applications for next-generation energy-saving technologies.

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