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Category: quantum physics – Page 342

Physicist Sean Carroll and the biggest ideas in the universe

Sean Carroll, a physicist at Johns Hopkins University, spoke at the Bell House in Brooklyn, New York, in an event presented by New York City’s Secret Science Club. He talked about quantum field theory, which is now considered the definitive explanation of what reality is made of. So, pretty important stuff.

His new book The Biggest Ideas in the Universe: Quanta and Fields was released this week. It’s the second in a three-book series in which he goes through the important ideas of Physics for non-academics, but actually using and carefully explaining the equations that physicists use.

Quantum entanglement expands to city-sized networks

The delicate nature of quantum information means it does not travel well. A quantum Internet therefore needs devices known as quantum repeaters to swap entanglement between quantum bits, or qubits, at intermediate points. Several researchers have taken steps towards this goal by distributing entanglement between multiple nodes.

In 2020, for example, Xiao-Hui Bao and colleagues in Jian-Wei Pan’s group at the University of Science and Technology of China (USTC) entangled two ensembles of rubidium-87 atoms in vapour cells using photons that had passed down 50 km of commercial optical fibre. Creating a functional quantum repeater is more complex, however: “A lot of these works that talk about distribution over 50,100 or 200 kilometres are just talking about sending out entangled photons, not about interfacing with a fully quantum network at the other side,” explains Can Knaut, a PhD student at Harvard University and a member of the US team.

The tunable coupling of two distant superconducting spin qubits

Quantum computers, computing devices that leverage the principles of quantum mechanics, could outperform classical computing on some complex optimization and processing tasks. In quantum computers, classical units of information (bits), which can either have a value of 1 or 0, are substituted by quantum bits or qubits, which can be in a mixture of both 0 and 1 simultaneously.

Plotnitsky’s New Perspective On Schrödinger’s Cat Experiment Challenges Quantum Understanding

I found this on NewsBreak.

The Schrödinger’s Cat Experiment, a paradox illustrating the concept of superposition in quantum mechanics, has been reinterpreted by Purdue University’s Professor Arkady Plotnitsky. His perspective, based on “reality without realism” (RWR) interpretations, suggests that the reality behind quantum phenomena is beyond conception. This view repositions classical physics as part of fundamental physics, a role typically reserved for quantum physics and relativity. This new interpretation challenges traditional understanding of the experiment and suggests our comprehension of reality is insufficient to fully grasp quantum phenomena. This perspective opens new research avenues in quantum physics and emphasizes the importance of philosophical considerations in physics study.

The Schrödinger’s Cat Experiment is a thought experiment proposed by physicist Erwin Schrödinger. It is a paradox that illustrates the concept of superposition in quantum mechanics. The experiment involves a cat that is placed in a sealed box with a radioactive source and a poison that will be released when the radioactive source decays. According to quantum mechanics, the cat is both alive and dead until the box is opened and the cat’s state is observed.

The experiment has been the subject of much debate and interpretation in the field of quantum physics. It challenges our understanding of reality and the nature of existence. The experiment is often used to illustrate the bizarre and counterintuitive nature of quantum mechanics, which operates on a scale that is far removed from our everyday experience.

Unlocking the Quantum Code: International Team Cracks a Long-Standing Physics Problem

“In quantum many-body theory, we are often faced with the situation that we can perform calculations using a simple approximate interaction, but realistic high-fidelity interactions cause severe computational problems,” says Dean Lee, Professor of Physics from the Facility for Rare Istope Beams and Department of Physics and Astronomy (FRIB) at Michigan State University and head of the Department of Theoretical Nuclear Sciences.

Practical Applications and Future Prospects

Wavefunction matching solves this problem by removing the short-distance part of the high-fidelity interaction and replacing it with the short-distance part of an easily calculable interaction. This transformation is done in a way that preserves all the important properties of the original realistic interaction. Since the new wavefunctions are similar to those of the easily computable interaction, the researchers can now perform calculations with the easily computable interaction and apply a standard procedure for handling small corrections – called perturbation theory.

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