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Category: quantum physics – Page 52

Single device amplifies signals while shielding qubits from unwanted noise

Quantum computing, an approach to deriving information that leverages quantum mechanical effects, relies on qubits, quantum units of information that can exist in superpositions of states. To effectively perform quantum computing, engineers and physicists need to be able to measure the state of qubits efficiently.

In quantum computers based on , qubits are indirectly measured by a so-called readout resonator, a circuit that responds differently based on the state of a . This circuit’s responses are probed using a weak electromagnetic wave, which needs to be amplified to enable its detection.

To amplify these signals, also known as microwave tones, quantum technology engineers rely on devices known as amplifiers. Existing amplifiers, however, have notable limitations. Conventional amplifiers can send unwanted noise back to the qubit, disturbing its state. Superconducting parametric amplifiers introduced more recently can be very efficient, but they conventionally rely on bulky and magnetic hardware components that control the direction of signal and protect qubits from backaction noise.

Ultrathin films of ferromagnetic oxide reveal a hidden Hall effect mechanism

Researchers from Japan have discovered a unique Hall effect resulting from deflection of electrons due to “in-plane magnetization” of ferromagnetic oxide films (SrRuO3). Arising from the spontaneous coupling of spin-orbit magnetization within SrRuO3 films, the effect overturns the century-old assumption that only out-of-plane magnetization can trigger the Hall effect.

The study, now published in Advanced Materials, offers a new way to manipulate with potential applications in advanced sensors, , and spintronic technologies.

When an electric current flows through a material in the presence of a magnetic field, its electrons experience a subtle sideways force which deflects their path. This effect of electron deflection is called the Hall effect—a phenomenon that lies at the heart of modern sensors and electronic devices. When this effect results from internal magnetization of the conducting material, it is called “anomalous Hall effect (AHE).”

Bayes’ Rule Goes Quantum: A 250-Year-Old Theory Learns New Tricks

An international team of researchers has identified a quantum counterpart to Bayes’ rule. The likelihood you assign to an event is influenced by what you already believe about the surrounding conditions. This is the basic principle of Bayes’ rule, a method for calculating probabilities first intr

New Method Proposed To Detect Universe’s Mysterious “Phantom Heat” Predicted by Einstein

The findings resolve a long-standing problem in fundamental physics. Scientists at Hiroshima University have created a practical and highly sensitive method for detecting the Unruh effect, a long-anticipated phenomenon that lies at the intersection of relativity and quantum theory. This new strat

Machine learning unravels quantum atomic vibrations in materials

Caltech scientists have developed an artificial intelligence (AI)–based method that dramatically speeds up calculations of the quantum interactions that take place in materials. In new work, the group focuses on interactions among atomic vibrations, or phonons—interactions that govern a wide range of material properties, including heat transport, thermal expansion, and phase transitions. The new machine learning approach could be extended to compute all quantum interactions, potentially enabling encyclopedic knowledge about how particles and excitations behave in materials.

Scientists like Marco Bernardi, professor of applied physics, physics, and at Caltech, and his graduate student Yao Luo (MS ‘24) have been trying to find ways to speed up the gargantuan calculations required to understand such particle interactions from first principles in real materials—that is, beginning with only a material’s atomic structure and the laws of quantum mechanics.

Last year, Bernardi and Luo developed a data-driven method based on a technique called singular value decomposition (SVD) to simplify the enormous mathematical matrices scientists use to represent the interactions between electrons and phonons in a material.

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