Using a quantum device, researchers have observed, for the first time, a molecular process called conical intersection that is important in reactions such as photosynthesis.
Quantum computers, technologies that perform computations leveraging quantum mechanical phenomena, could eventually outperform classical computers on many complex computational and optimization problems. While some quantum computers have attained remarkable results on some tasks, their advantage over classical computers is yet to be conclusively and consistently demonstrated.
Ramis Movassagh, a researcher at Google Quantum AI, who was formerly at IBM Quantum, recently carried out a theoretical study aimed at mathematically demonstrating the notable advantages of quantum computers. His paper, published in Nature Physics, mathematically shows that simulating random quantum circuits and estimating their outputs is so-called #P-hard for classical computers (i.e., meaning that is highly difficult).
“A key question in the field of quantum computation is: Are quantum computers exponentially more powerful than classical ones?” Ramis Movassagh, who carried out the study, told Phys.org. “Quantum supremacy conjecture (which we renamed to Quantum Primacy conjecture) says yes. However, mathematically it’s been a major open problem to establish rigorously.”
Perovskite light-emitting diode is used as the light source for a quantum random number generator used in encryption.
Encryption plays an important role in protecting information in this digital era, and a random number generator plays a vital part in this by providing keys that are used to both encrypt and unlock the information at the receiving end.
Now, a team of researchers has made use of light-emitting diodes made from the crystal-like material perovskite to devise a new type of Quantum Random Number Generator (QRNG) that can be used for encryption but also for betting and computer simulations.
National University of Singapore (NUS) scientists demonstrated a conceptual breakthrough by fabricating atomically precise quantum antidots (QAD) using self-assembled single vacancies (SVs) in a two-dimensional (2D) transition metal dichalcogenide (TMD).
Quantum dots confine electrons on a nanoscale level. In contrast, an antidot refers to a region characterized by a potential hill that repels electrons. By strategically introducing antidot patterns (“voids”) into carefully designed antidot lattices, intriguing artificial structures emerge.
These structures exhibit periodic potential modulation to change 2D electron behavior, leading to novel transport properties and unique quantum phenomena. As the trend towards miniaturized devices continue, it is important to accurately control the size and spacing of each antidot at the atomic level. This control together with resilience to environmental perturbations is crucial to address technological challenges in nanoelectronics.
Scientists have been able to observe a common interaction in quantum chemistry for the first time, by using a quantum computer to shadow the process at a speed 100 billion times slower than normal.
Known as a conical intersection, the interactions have long been known about, but are usually over in mere femtoseconds – quadrillionths of a second – making direct observations impossible to carry out.
Non-perturbative interactions (i.e., interactions too strong to be described by so-called perturbation theory) between light and matter have been the topic of numerous research studies. Yet the role that quantum properties of light play in these interactions and the phenomena arising from them have so far remained widely unexplored.
Researchers at Technion–Israel Institute of Technology recently introduced a new theory describing the physics underpinning non-perturbative interactions driven by quantum light. Their theory, introduced in Nature Physics, could guide future experiments probing strong-field physics phenomena, as well as the development of new quantum technology.
This recent paper was the result of a close collaboration between three different research groups at Technion, led by principal investigators Prof. Ido Kaminer, Prof. Oren Cohen and Prof. Michael Krueger. Students Alexey Gorlach and Matan Even Tsur, co-first authors of the paper, spearheaded the study, with support and ideas from Michael Birk and Nick Rivera.
Digital information exchange can be safer, cheaper and more environmentally friendly with the help of a new type of random number generator for encryption developed at Linköping University, Sweden. The researchers behind the study believe that the new technology paves the way for a new type of quantum communication.
In an increasingly connected world, cybersecurity is becoming increasingly important to protect not just the individual, but also, for example, national infrastructure and banking systems. And there is an ongoing race between hackers and those trying to protect information. The most common way to protect information is through encryption. So when we send emails, pay bills and shop online, the information is digitally encrypted.
To encrypt information, a random number generator is used, which can either be a computer program or the hardware itself. The random number generator provides keys that are used to both encrypt and unlock the information at the receiving end.
In a study published in Matter, researchers led by Prof. Yang Zhaorong and Prof. Hao Ning from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences found that the quasi-one-dimensional charge density wave (CDW) material cupric telluride (CuTe) provides a rare and promising platform for the study of multiple CDW orders and superconductivity under high pressure.
The interplay between superconductivity and CDW has always been one of the central issues in the research of condensed matter physics. While theory generally predicts that they compete with each other, superconductivity and CDW can manifest complex relationships under external stimuli in practical materials. Additionally, recent research in the superconducting cuprates and the Kagome CsV3Sb5 has found that superconductivity interacts with multiple CDW orders. However, in the above two systems, there are some other quantum orders in the phase diagrams, which hinders a good understanding of the interplay between superconductivity and multiple CDWs.
In this study, the researchers provided solid evidence for a second CDW order in the quasi-one-dimensional CDW material CuTe under high pressure. In addition, they found that superconductivity can be induced and that it has complex relationships with the native and emergent CDW orders.
Researchers have developed a way to address many quantum dots with only a few control lines using a chessboard-like method. This enabled the operation of the largest gate-defined quantum dot system ever. Their result is an important step in the development of scalable quantum systems for practical quantum technology.
Quantum dots can be used to hold qubits, the foundational building blocks of a quantum computer. Currently, each qubit requires its own addressing line and dedicated control electronics. This is highly impractical and in stark contrast with today’s computer technology, where billions of transistors are operated with only a few thousand lines.
A new nanoscience study led by a researcher at the Department of Energy’s Oak Ridge National Laboratory takes a big-picture look at how scientists study materials at the smallest scales.
The paper, published in Science Advances, reviews leading work in subsurface nanometrology, the science of internal measurement at the nanoscale level, and suggests quantum sensing could become the foundation for the field’s next era of discoveries. Potential applications could range from mapping intracellular structures for targeted drug delivery to characterizing quantum materials and nanostructures for the advancement of quantum computing.
“Our goal was to define the state of the art and to consider what’s been done and where we need to go,” said Ali Passian, an ORNL senior research scientist and senior author of the study.
