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Category: quantum physics – Page 7

A new approach to probing Landauer’s principle in the quantum many-body regime

Landauer’s principle is a thermodynamics concept also relevant in information theory, which states that erasing one bit of information from an information system results in the dissipation of at least a specific amount (i.e., kBTln2) of energy. This principle has so far been primarily considered in the context of classical computers and information processing systems.

Yet researchers at TU Vienna, the Freie Universität Berlin, the University of British Columbia, the University of Crete and the Università di Pavia recently extended Landauer’s principle to quantum many-body systems, systems made up of many interacting .

Their paper, published in Nature Physics, introduces a viable approach to experimentally probe this crucial principle in a quantum regime and test rooted in quantum thermodynamics.

New hybrid quantum–classical computing approach used to study chemical systems

Caltech professor of chemistry Sandeep Sharma and colleagues from IBM and the RIKEN Center for Computational Science in Japan are giving us a glimpse of the future of computing. The team has used quantum computing in combination with classical distributed computing to attack a notably challenging problem in quantum chemistry: determining the electronic energy levels of a relatively complex molecule.

The work demonstrates the promise of such a quantum–classical hybrid approach for advancing not only , but also fields such as , nanotechnology, and drug discovery, where insight into the electronic fingerprint of materials can reveal how they will behave.

“We have shown that you can take classical algorithms that run on high-performance classical computers and combine them with quantum algorithms that run on quantum computers to get useful chemical results,” says Sharma, a new member of the Caltech faculty whose work focuses on developing algorithms to study quantum . “We call this quantum-centric supercomputing.”

Boson sampling finds first practical applications in quantum AI

For over a decade, researchers have considered boson sampling—a quantum computing protocol involving light particles—as a key milestone toward demonstrating the advantages of quantum methods over classical computing. But while previous experiments showed that boson sampling is hard to simulate with classical computers, practical uses have remained out of reach.

Now, in Optica Quantum, researchers from the Okinawa Institute of Science and Technology (OIST) present the first practical application of boson sampling for image recognition, a vital task across many fields, from forensic science to medical diagnostics. Their approach uses just three photons and a linear optical network, marking a significant step towards low energy quantum AI systems.

Smart amplifier cuts power consumption, paving way for more qubits and less decoherence

Quantum computers can solve extraordinarily complex problems, unlocking new possibilities in fields such as drug development, encryption, AI, and logistics. Now, researchers at Chalmers University of Technology in Sweden have developed a highly efficient amplifier that activates only when reading information from qubits. The study was published in the journal IEEE Transactions on Microwave Theory and Techniques.

Thanks to its smart design, it consumes just one-tenth of the power consumed by the best amplifiers available today. This reduces decoherence and lays the foundation for more with significantly more qubits and enhanced performance.

Bits, which are the building blocks of a conventional computer, can only ever have the value of 1 or 0. By contrast, the common building blocks of a quantum computer, quantum bits or qubits, can exist in states having the value 1 and 0 simultaneously, as well as all states in between in any combination.

“We’re Rewiring the Future”: MIT’s Superconducting Chip Breakthrough Could Unlock the True Power of Quantum Computing

IN A NUTSHELL 🔬 MIT researchers have developed a superconducting diode-based rectifier that converts AC to DC on a single chip. 💡 This innovation could streamline power delivery in ultra-cold quantum systems, reducing electromagnetic noise and interference. 🔍 The technology is crucial for enhancing qubit stability and could significantly impact dark matter detection circuits at

Breakthrough theory links Einstein’s relativity and quantum mechanics

For over 100 years, two theories have shaped our understanding of the universe: quantum mechanics and Einstein’s general relativity. One explains the tiny world of particles; the other describes gravity and the fabric of space. But despite their individual success, bringing them together has remained one of science’s greatest unsolved problems.

Now, a team of researchers at University College London has introduced a bold new idea. Rather than tweaking Einstein’s theory to fit into quantum rules, they suggest flipping the script. Their model, called a “postquantum theory of classical gravity,” aims to rethink the deep link between gravity and the quantum world.

Quantum mechanics thrives on probabilities, uncertainty, and the strange behavior of subatomic particles. It’s helped explain the structure of atoms and power modern technology. Meanwhile, general relativity offers a grand view of the universe, where planets and stars bend spacetime and create what we feel as gravity.

New Approach to Controlling Light Signals

A concept based on an exotic effect in periodic structures may be useful for developing future photonic devices.

A new way to marshal light within optical devices has been demonstrated experimentally by researchers in China. They have been able to induce light to organize itself into specific patterns of pulses as it circulates within a pair of optical fiber loops using a version of a phenomenon—called the non-Hermitian skin effect (NHSE)—that has been predicted but not observed previously [1]. The effect could be used to control light signals in photonic devices such as switches and routers.

In the standard theory for electron behavior in a metallic crystal, the periodic atomic structure leads to so-called Bloch waves—electron quantum states that spread across the entire crystal. But in recent years, theorists have found surprising results for a scenario in which one assumes that a particle such as an electron hops between neighboring sites in a periodic lattice asymmetrically—say, rightward hopping is more probable than leftward hopping. The particle’s quantum states become localized at the edge or surface of the lattice rather than spreading across it. This localization is the NHSE.

Quantum spin currents in graphene without external magnetic fields pave way for ultra-thin spintronics

Scientists from TU Delft (The Netherlands) have observed quantum spin currents in graphene for the first time without using magnetic fields. These currents are vital for spintronics, a faster and more energy-efficient alternative to electronics. This breakthrough, published in Nature Communications, marks an important step towards technologies like quantum computing and advanced memory devices.

Quantum physicist Talieh Ghiasi has demonstrated the quantum Hall (QSH) effect in graphene for the first time without any external magnetic fields. The QSH effect causes electrons to move along the edges of the graphene without any disruption, with all their spins pointing in the same direction.

“Spin is a quantum mechanical property of electrons, which is like a tiny magnet carried by the electrons, pointing up or down,” Ghiasi explains. “We can leverage the spin of electrons to transfer and process information in so-called spintronics devices. Such circuits hold promise for next-generation technologies, including faster and more energy-efficient electronics, quantum computing, and advanced memory devices.”