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Category: quantum physics – Page 252

Researchers from the RIKEN Center for Quantum Computing have used machine learning to perform error correction for quantum computers—a crucial step for making these devices practical—using an autonomous correction system that despite being approximate, can efficiently determine how best to make the necessary corrections.

The research is published in the journal Physical Review Letters.

In contrast to , which operate on bits that can only take the basic values 0 and 1, quantum computers operate on “qubits”, which can assume any superposition of the computational basis states. In combination with , another quantum characteristic that connects different qubits beyond classical means, this enables quantum computers to perform entirely new operations, giving rise to potential advantages in some computational tasks, such as large-scale searches, , and cryptography.

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Scientists from the University of Ottawa have invented a unique method to create better molecule-based magnets, known as single-molecule magnets (SMMs). This synthetic tour de force has resulted in a two-coordinate lanthanide complex which has magnet-like properties that are intrinsic to the molecule itself. This advancement paves the way for high-capacity hard drives, potential applications in quantum computing.

Performing computation using quantum-mechanical phenomena such as superposition and entanglement.

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Almost a century ago, physicists Satyendra Nath Bose and Albert Einstein predicted a theoretical state of matter in which individual particles would, at extremely cold temperatures and low densities, condense into an indistinguishable whole. These so-called Bose-Einstein condensates (BECs) would offer a macroscopic view into the microscopic world of quantum mechanics. In 1995, theoretical BECs became an experimental reality, which garnered the physicists who created them a Nobel Prize. Labs around the world— and even in space —have been creating them ever since.

All of the BECs created so far to ask fundamental questions about quantum mechanics have been made from atoms. It has proven much harder to make molecules cold enough to approach a BEC state, which hover fractions of a degree above absolute zero, and to keep the molecules stable long enough to conduct experiments.

“For twenty years, there have been proposals about what you could do with stable ultracold molecules, but it has been tough on the experimental side because the lifetime of molecular samples has been short,” said Columbia physicist Sebastian Will, whose lab specializes in creating ultracold atoms and molecules.

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Never let it be said that scientists don’t have an eye for the sublime.

Encoding and deciphering a Chinese symbol for duality and harmony into the quantum states of two entangled photons, physicists recently demonstrated the superior efficiency of a new analytical technique.

Researchers from the Sapienza University of Rome and the University of Ottawa in Canada used a method similar to a popular holographic technique to quickly and reliably measure information of a particle’s position.

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Quantum technology’s future rests on the exploitation of fascinating quantum mechanics concepts—such as high-dimensional quantum states. Think of these states as basic ingredients of quantum information science and quantum tech. To manipulate these states, scientists have turned to light, specifically a property called orbital angular momentum (OAM), which deals with how light twists and turns in space. Here’s a catch: making super bright single photons with OAM in a deterministic fashion has been a tough nut to crack.

Now, enter (QDs), tiny particles with big potential. A team of researchers from Sapienza University of Rome, Paris-Saclay University, and University of Naples Federico II combined the features of OAM with those of QDs to create a bridge between two cutting-edge technologies.

Their results are published in Advanced Photonics.

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Does hot water freeze faster than cold water? Aristotle may have been the first to tackle this question that later became known as the Mpemba effect.

This phenomenon originally referred to the non-monotonic initial temperature dependence of the freezing start time, but it has been observed in various systems — including colloids — and has also become known as a mysterious relaxation phenomenon that depends on initial conditions.

However, very few have previously investigated the effect in quantum systems.

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Year 2022 Infinite quantum computer :3.

The scaling of the entanglement entropy at a quantum critical point allows us to extract universal properties of the state, e.g., the central charge of a conformal field theory. With the rapid improvement of noisy intermediate-scale quantum (NISQ) devices, these quantum computers present themselves as a powerful tool to study critical many-body systems. We use finite-depth quantum circuits suitable for NISQ devices as a variational ansatz to represent ground states of critical, infinite systems. We find universal finite-depth scaling relations for these circuits and verify them numerically at two different critical points, i.e., the critical Ising model with an additional symmetry-preserving term and the critical XXZ model.

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For years, researchers have tried various ways to coax quantum bits—or qubits, the basic building blocks of quantum computers—to remain in their quantum state for ever-longer times, a key step in creating devices like quantum sensors, gyroscopes, and memories.

A team of physicists from MIT have taken an important step forward in that quest, and to do it, they borrowed a concept from an unlikely source—noise-cancelling headphones.

Led by Ju Li, the Battelle Energy Alliance Professor in Nuclear Engineering and professor of materials science and engineering, and Paola Cappellaro, the Ford Professor of Engineering in the Department of Nuclear Science and Engineering and Research Laboratory of Electronics, and a professor of physics, the team described a method to achieve a 20-fold increase in the coherence times for nuclear-spin qubits.

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