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Category: quantum physics – Page 88

To develop scalable and reliable quantum computers, engineers and physicists will need to devise effective strategies to mitigate errors in their quantum systems without adding complex additional components. A promising strategy to reduce errors entails the use of so-called dual-type qubits.

These are qubits that can encode in a system across two different types of quantum states. These qubits could increase the flexibility of quantum computing architectures, while also reducing undesirable crosstalk between qubits and enhancing a system’s operational fidelity.

Researchers at Tsinghua University and other research institutes in China recently realized an entangling gate between dual-type qubits in an experimental setting.

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It’s expected that the technology will tackle myriad problems that were once deemed impractical or even impossible to solve. Quantum computing promises huge leaps forward for fields spanning drug discovery and materials development to financial forecasting.

But just as exciting as quantum computing’s future are the breakthroughs already being made today in quantum hardware, error correction and algorithms.

NVIDIA is celebrating and exploring this remarkable progress in quantum computing by announcing its first Quantum Day at GTC 2025 on Thursday, March 20. This new focus area brings together leading experts for a comprehensive and balanced perspective on what businesses should expect from quantum computing in the coming decades — mapping the path toward useful quantum applications.

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Symmetry plays a crucial role in understanding fundamental phenomena such as conservation laws, the classification of phases of matter, and their transitions. Recently, researchers have been exploring ways to manipulate symmetries in quantum many-body systems with time-dependent driving protocols and, in particular, engineering new symmetries that do not naturally occur. This significantly enriches the toolbox for quantum simulation and computation, and has led to many exciting discoveries of nonequilibrium phases such as discrete time crystals. However, controlling multiple symmetries—especially in a simple and experimentally friendly way—has remained a challenge. In this work, we propose a novel method to engineer hierarchical symmetries by time-dependent protocols.

By carefully controlling how symmetry-indicating observables evolve over time, we show how to create a sequence of symmetries that emerge one after another, each with distinct properties. Our method relies on a recursive construction that hierarchically minimizes the effects of symmetry-breaking processes. This leads to a corresponding sequence of prethermal steady states with controllable lifetimes, each exhibiting a lower symmetry than the preceding one. We illustrate this protocol with several examples, demonstrating how different types of order can emerge through hierarchical symmetry breaking.

This toolbox of hierarchical symmetries opens a new path to stabilizing quantum states and controlling unwanted symmetry-breaking effects, which can be particularly useful in quantum computing and quantum simulation. The construction applies to classical and quantum, fermionic and bosonic, interacting and noninteracting systems. The underlying mechanism generalizes state-of-the-art dynamical decoupling techniques and is implementable on present-day quantum simulation platforms.

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The operation and performance of quantum computers relies on the ability to realize and control entanglement between multiple qubits. Yet entanglement between many qubits is inherently susceptible to noise and imperfections in quantum gates.

In recent years, and engineers worldwide have thus been trying to develop more robust protocols to realize and control entanglement. To be most effective for real-world applications, these approaches should reliably support long-range entanglement, or in other words ensure that qubits remain entangled even when they are separated by large distances.

Researchers at IBM Quantum, University of Cologne and Harvard University set out to demonstrate one of these protocols in an experimental setting.

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Physicists have spent more than a century measuring and making sense of the strange ways that photons, electrons, and other subatomic particles interact at extremely small scales. Engineers have spent decades figuring out how to take advantage of these phenomena to create new technologies.

In one such phenomenon, called , pairs of photons become interconnected in such a way that the state of one instantly changes to match the state of its paired photon, no matter how far apart they are.

Nearly 80 years ago, Albert Einstein referred to this phenomenon as “spooky action at a distance.” Today, entanglement is the subject of research programs across the world—and it’s becoming a favored way to implement the most fundamental form of quantum information, the qubit.

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Quantum computing promises to solve complex problems exponentially faster than a classical computer, by using the principles of quantum mechanics to encode and manipulate information in quantum bits (qubits).

Qubits are the building blocks of a quantum computer. One challenge to scaling, however, is that qubits are highly sensitive to background noise and control imperfections, which introduce errors into the quantum operations and ultimately limit the complexity and duration of a quantum algorithm. To improve the situation, MIT researchers and researchers worldwide have continually focused on improving qubit performance.

In new work, using a superconducting qubit called fluxonium, MIT researchers in the Department of Physics, the Research Laboratory of Electronics (RLE), and the Department of Electrical Engineering and Computer Science (EECS) developed two new control techniques to achieve a world-record single-qubit fidelity of 99.998%. This result complements then-MIT researcher Leon Ding’s demonstration last year of a 99.92% two-qubit gate fidelity.

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Science is always looking for more computing power and more efficient tools capable of answering its questions. Quantum computers are the new frontier in data processing, as they use the quantum properties of matter, such as the superposition of states and entanglement, to perform very complex operations.

A research team coordinated by the Department of Physics of the University of Trento had the opportunity to test some hypotheses on confinement in Z2 lattice gauge theory on the quantum computers of Google’s Quantum Artificial Intelligence Lab, in California. Their work was published in Nature Physics.

Gauge theories describe the fundamental forces in the and play an important role in condensed matter physics. The constituents of gauge theories, such as charged matter and electric gauge field, are governed by local gauge constraints, which lead to key phenomena that are not yet fully understood. In this context, quantum simulators may offer solutions that cannot be reached using conventional computers.

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