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A method to compute the Rényi entanglement entropy in auxiliary-field quantum Monte Carlo simulations

Entanglement is a widely studied quantum physics phenomenon, in which two particles become linked in such a way that the state of one affects the state of another, irrespective of the distance between them. When studying systems comprised of several strongly interacting particles (i.e., many body systems) in two or more dimensions, numerically predicting the amount of information shared between these particles, a measure known as entanglement entropy (EE), becomes highly challenging.

Magnetic avalanche triggered by quantum effects

Iron screws and other so-called ferromagnetic materials are made up of atoms with electrons that act like little magnets. Normally, the orientations of the magnets are aligned within one region of the material but are not aligned from one region to the next. Think of packs of tourists in Times Square pointing to different billboards all around them. But when a magnetic field is applied, the orientations of the magnets, or spins, in the different regions line up and the material becomes fully magnetized. This would be like the packs of tourists all turning to point at the same sign.

The parallel universes of a sci-fi visionary named Philip K. Dick

To understand the relationship between the science fiction genre and the Many-Worlds Interpretation, let’s turn to two men – a scientist and a writer. The scientist is Hugh Everett III (1930−1982), a physicist who developed the notion of parallel universes based on an original interpretation of quantum mechanics. He proposed that a pre-formulated theory should be the basis of scientific measurement, quite the opposite of the traditional scientific process in which measurement preceded and determined the theory. But quantum particles do not behave normally, so quantum phenomena and their atomic dynamics cannot be measured by the Newtonian mechanics traditionally applied to the universe.

When Hugh Everett published “Relative State Formulation of Quantum Mechanics” in the Reviews of Modern Physics scientific journal (Volume 29, Issue 3, July — September 1957), his theory that there are many worlds existing in parallel at the same space and time as our own sounded like fantasy fiction to a skeptical scientific world.

While scientists scoffed for more than a decade after Everett published his theory, someone else entered the scene. His name was Philip K. Dick, a scruffy beatnik writer who tramped around Berkeley (California) looking for ways to describe this alternative reality – the one hiding behind our visible reality.

Quantum interference could lead to smaller, faster, and more energy-efficient transistors

As transistors get smaller, they become increasingly inefficient and susceptible to errors, as electrons can leak through the device even when it is supposed to be switched off, by a process known as quantum tunneling. Researchers are exploring new types of switching mechanisms that can be used with different materials to remove this effect.

In the nanoscale structures that Professor Jan Mol, Dr. James Thomas, and their group study at Queen Mary’s School of Physical and Chemical Sciences, quantum mechanical effects dominate, and electrons behave as waves rather than particles. Taking advantage of these quantum effects, the researchers built a new transistor.

The transistor’s conductive channel is a single zinc porphyrin, a molecule that can conduct electricity. The porphyrin is sandwiched between two graphene electrodes, and when a voltage is applied to the electrodes, electron flow through the molecule can be controlled using .

Physicists Capture Elusive 4D ‘Ghost’ in CERN Particle Accelerator

There’s a specter haunting the tunnels of a particle accelerator at CERN.

In the Super Proton Synchrotron, physicists have finally measured and quantified an invisible structure that can divert the course of the particles therein, and create problems for particle research.

It’s described as taking place in phase space, which can represent one or more states of a moving system. Since four states are required to represent the structure, the researchers view it as four-dimensional.

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