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Category: quantum physics – Page 166

Trapped-ion processor demonstrates verifiable quantum random sampling

One of the key goals within the field of quantum computing is to achieve what is known as a quantum advantage. This term essentially describes the point after which a quantum computer can outperform a classical computer on a specific task or solve a problem that is beyond the reach of classical computers.

One task that could be used to demonstrate a , known as quantum random sampling, entails the generation of samples from a probability distribution. This task is very difficult for classical computers to perform, but it could theoretically be completed by quantum computers.

While past studies have successfully tackled random sampling tasks using quantum computers, actually verifying that a system effectively performs these tasks has proved challenging. This is because many existing verification techniques based on classical data are either too computationally demanding or difficult to apply to larger quantum systems.

Case study demonstrates practical applications for quantum machine learning

Quantum researchers from CSIRO, Australia’s national science agency, have demonstrated the potential for quantum computing to significantly improve how we solve complex problems involving large datasets, highlighting the potential of using quantum in areas such as real-time traffic management, agricultural monitoring, health care, and energy optimization.

By leveraging the unique properties of quantum computing, like superposition and entanglement, researchers compressed and analyzed a large dataset with speed, accuracy, and efficiency that traditional computers cannot match.

The work is published in the journal Advanced Science.

New avenues in quantum research: Supramolecular chemistry detects qubit candidates

A Franco-German research team, including members from the University of Freiburg, shows that supramolecular chemistry enables efficient spin communication through hydrogen bonds. The work is published in the journal Nature Chemistry.

Qubits are the basic building blocks of information processing in quantum technology. An important research question is what material they will actually consist of in technical applications. Molecular spin qubits are considered promising qubit candidates for molecular spintronics, in particular for quantum sensing. The materials studied here can be stimulated by light; this creates a second spin center and, subsequently, a light-induced quartet state.

Until now, research has assumed that the interaction between two spin centers can only be strong enough for successful quartet formation if the centers are covalently linked. Due to the high effort required to synthesize covalently bonded networks of such systems, their use in application-related developments in the field of quantum technology is severely limited.

D-Wave Quantum price target raised to $8.50 from $2.25 at Needham

Needham raised the firm’s price target on D-Wave Quantum (QBTS) to $8.50 from $2.25 and keeps a Buy rating on the shares as part of a broader research note on Quantum Computing names. Over the past several months, the combination of technical milestone achievements, announcements of quantum contract awards of increasing dollar value and mentions of quantum computing by leading technology CEOs has increased awareness of the potential opportunity for quantum computing among mainstream investors, and reflecting this increased awareness, the stock prices of pure play quantum computing companies have increased several fold since September 30, 2024, the analyst tells investors in a research note. s. 5.9% for the S&P 500. The increasing valuations for quantum computing companies reflect growing recognition that quantum computing may disrupt a meaningful portion of the $1T computing market over the next decade, the firm added.

Theorists propose a completely new class of quantum particles

In a ground-breaking theoretical study, two physicists have identified a new class of quasiparticle called the paraparticle. Their calculations suggest that paraparticles exhibit quantum properties that are fundamentally different from those of familiar bosons and fermions, such as photons and electrons respectively.

Using advanced mathematical techniques, Kaden Hazzard at Rice University in the US and his former graduate student Zhiyuan Wang, now at the Max Planck Institute of Quantum Optics in Germany, have meticulously analysed the mathematical properties of paraparticles and proposed a real physical system that could exhibit paraparticle behaviour.

“Our main finding is that it is possible for particles to have exchange statistics different from those of fermions or bosons, while still satisfying the important physical principles of locality and causality,” Hazzard explains.

Programmable simulations of molecules and materials with reconfigurable quantum processors

For example, to compute the magnetic susceptibility, we simply select the operator \(A=\beta {({S}^{z})}^{2}\), where β = 1/T is the inverse temperature. Interestingly, this method of estimating thermal expectation values is insensitive to uniform spectral broadening of each peak, due to a cancellation between the numerator and denominator (see discussion resulting in equation (S69) in Supplementary Information). However, it is highly sensitive to noise at low ω, which is exponentially amplified by e−βω. To address this, we estimate the SNR for each DA(ω) independently and zero-out all points with SNR below three times the average SNR. This potentially introduces some bias by eliminating peaks with low signal but ensures that the effects of shot noise are well controlled.

To quantify the effect of noise on the engineered time dynamics, we simulate a microscopic error model by applying a local depolarizing channel with an error probability p at each gate. This results in a decay of the obtained signals for the correlator \({D}_{R}^{A}(t)\). The rate of the exponential decay grows roughly linearly with the weight of the measured operators (Extended Data Fig. 2). This scaling with operator weight can be captured by instead applying a single depolarizing channel at the end of the time evolution, with a per-site error probability of γt with an effective noise rate γ. This effective γ also scales roughly linear as a function of the single-qubit error rate per gate p (Extended Data Fig. 2).

Quantum simulations are constrained by the required number of samples and the simulation time needed to reach a certain target accuracy. These factors are crucial for determining the size of Hamiltonians that can be accessed for particular quantum hardware.

Harnessing atom-light interactions: A step towards stable quantum systems

Interactions between atoms and light rule the behavior of our physical world, but at the same time, can be extremely complex. Understanding and harnessing them is one of the major challenges for the development of quantum technologies.

To understand light-mediated interactions between atoms, it is common to isolate only two atomic levels, a ground level and an excited level, and view the atoms as tiny antennas with two poles that talk to each other. So, when an atom in a crystal lattice array is prepared in the , it relaxes back to the after some time by emitting a photon.

The emitted photon does not necessarily escape from the array, but instead, it can become absorbed by another ground-state atom, which then gets excited. Such an exchange of excitations, also referred to as dipole-dipole interaction, is key for making atoms interact, even when they cannot bump into each other.

Exploring a new qubit with the gemstone spinel

The gemstone spinel, known for its vibrant colors resembling gems such as rubies and sapphires, has now been shown to be capable of storing quantum information, making it a viable material in the field of quantum technology.

The discovery, which was made by collaborators from Tohoku University, the University of Chicago, and Argonne National Laboratory, was published in the journal Applied Physics Express.

This is the first paper resulting from the Chicago–Tohoku Quantum Alliance. The alliance between UChicago and Tohoku researchers was forged in June 2023 to help build bridges with Japanese companies and establish stronger industry ties with academia and government.

A new experimental system to bring quantum technologies closer to students

The world of quantum physics is experiencing a second revolution, which will drive an exponential leap in the progress of computing, the internet, telecommunications, cybersecurity and biomedicine.

Quantum technologies are attracting more and more students who want to learn about concepts from the subatomic world—such as quantum entanglement or —to explore the innovative potential of quantum science.

In fact, understanding the non-intuitive nature of quantum technology concepts and recognizing their relevance to technological progress is one of the challenges of 2025, declared the International Year of Quantum Science and Technology by UNESCO.

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