Quantum effects improve the performance of magnetic induction tomography—an imaging technique that has promising medical applications.
Category: quantum physics – Page 469
Testing Gravity’s Effect on Quantum Spins
A new search for an interaction between a particle’s intrinsic spin and Earth’s gravitational field probes physics in the regime where quantum theory meets gravity.
Our understanding of physics is supported by two theoretical pillars. The first is quantum field theory, which underpins the standard model of particle physics. And the second is Einstein’s theory of general relativity, which describes the nature of gravity. Both pillars have withstood numerous stringent tests and have had myriad predictions spectacularly confirmed. Yet they are seemingly irreconcilable, hinting at a deeper truth. The path toward reconciling these theories is obscured by the dearth of experiments probing phenomena at the intersection of quantum physics and gravity. Now a team of researchers from the University of Science and Technology of China (USTC), led by Dong Sheng and Zheng-Tian Lu, has stepped into this breach by searching for an interaction between a particle’s intrinsic quantum spin and Earth’s gravitational field with unprecedented sensitivity (Fig. 1) [1].
Team demonstrates quantum advantage on optimization problems with a 5,000-qubit programmable spin glass
Over the past decades, researchers and companies worldwide have been trying to develop increasingly advanced quantum computers. The key objective of their efforts is to create systems that will outperform classical computers on specific tasks, which is also known as realizing “quantum advantage.”
A research team at D-Wave Quantum Inc., a Canadian quantum computing company, recently created a new quantum computing system that outperforms classical computing systems on optimization problems. This system, introduced in a paper in Nature, is based on a programmable spin glass with 5,000 qubits (the quantum equivalents of bits in classical computing).
“This work validates the original hypothesis behind quantum annealing, coming full circle from some seminal experiments conducted in the 1990s,” Andrew D. King, one of the researchers who carried out the study, told Phys.org.
Google Quantum AI Braids Non-Abelian Anyons — A Breakthrough That Could Revolutionize Quantum Computing
In a paper published in the journal Nature on May 11, researchers at Google Quantum AI announced that they had used one of their superconducting quantum processors to observe the peculiar behavior of non-Abelian anyons for the first time ever. They also demonstrated how this phenomenon could be used to perform quantum computations. Earlier this week the quantum computing company Quantinuum released another study on the topic, complementing Google’s initial discovery. These new results open a new path toward topological quantum computation, in which operations are achieved by winding non-Abelian anyons around each other like strings in a braid.
Google Quantum AI team member and first author of the manuscript, Trond I. Andersen says, “Observing the bizarre behavior of non-Abelian anyons for the first time really highlights the type of exciting phenomena we can now access with quantum computers.”
Imagine you’re shown two identical objects and then asked to close your eyes. Open them again, and you see the same two objects. How can you determine if they have been swapped? Intuition says that if the objects are truly identical, there is no way to tell.
Curved spacetime in a quantum simulator
The theory of relativity works well when you want to explain cosmic-scale phenomena—such as the gravitational waves created when black holes collide. Quantum theory works well when describing particle-scale phenomena—such as the behavior of individual electrons in an atom. But combining the two in a completely satisfactory way has yet to be achieved. The search for a “quantum theory of gravity” is considered one of the significant unsolved tasks of science.
This is partly because the mathematics in this field is highly complicated. At the same time, it is tough to perform suitable experiments: One would have to create situations in which phenomena of both the relativity theory play an important role, for example, a spacetime curved by heavy masses, and at the same time, quantum effects become visible, for example the dual particle and wave nature of light.
At the TU Wien in Vienna, Austria, a new approach has now been developed for this purpose: A so-called “quantum simulator” is used to get to the bottom of such questions: Instead of directly investigating the system of interest (namely quantum particles in curved spacetime), one creates a “model system” from which one can then learn something about the system of actual interest by analogy. The researchers have now shown that this quantum simulator works excellently.
Weird particle that remembers its past discovered by quantum computer
Particles with unusual properties called anyons have long been sought after as a potential building block for advanced quantum computers, and now researchers have found one – using a quantum computer.
By Alex Wilkins
Engineering graphene-based quantum circuits with atomic precision
😗😁
Imagine having a building made of stacks of bricks connected by adaptable bridges. You pull a knob that modifies the bridges and the building changes functionality. Wouldn’t it be great?
A team of researchers led by Prof. Aitor Mugarza, from the Catalan Institute of Nanoscience and Nanotechnology (ICN2) and ICREA, together with Prof. Diego Peña from the Center for Research in Biological Chemistry and Molecular Materials of the University of Santiago de Campostela (CiQUS-USC), Dr. Cesar Moreno, formerly a member of ICN2’s team and currently a researcher at the University of Cantabria, and Dr. Aran Garcia-Lekue, from the Donostia International Physics Center (DIPC) and Ikerbasque Foundation, has done something analogous, but at the single-atom scale, with the aim of synthesizing new carbon-based materials with tunable properties.
As explained in a paper just published in the Journal of the American Chemical Society (JACS) and featured on the cover of the issue, this research is a significant breakthrough in the precise engineering of atomic-thin materials —called “2D materials” due to their reduced dimensionality. The proposed fabrication technique opens exciting new possibilities for materials science, and, in particular, for application in advanced electronics and future solutions for sustainable energy.
Supercomputing simulations spot electron orbital signatures
Something not musk:
No one will ever be able to see a purely mathematical construct such as a perfect sphere. But now, scientists using supercomputer simulations and atomic resolution microscopes have imaged the signatures of electron orbitals, which are defined by mathematical equations of quantum mechanics and predict where an atom’s electron is most likely to be.
Scientists at UT Austin, Princeton University, and ExxonMobil have directly observed the signatures of electron orbitals in two different transition-metal atoms, iron (Fe) and cobalt (Co) present in metal-phthalocyanines. Those signatures are apparent in the forces measured by atomic force microscopes, which often reflect the underlying orbitals and can be so interpreted.
Their study was published in March 2023 as an Editors’ Highlight in the journal Nature Communications.