Researchers at the University of Chicago have figured out how to improve the performance of diamond-based quantum sensors by studying defects at the atomic level.
These sensors, which use nitrogen vacancy (NV) centers in diamonds to measure magnetic fields, often struggle with interference from nearby defects. The new method isolates these disruptive elements, promising better sensors for future use in navigation and healthcare technologies.
Quantum Defects and Their Applications
Quantum defects hold great potential as ultra-sensitive sensors, with possible applications in advanced navigation systems and biological sensing technologies.
A key example of these systems is nitrogen vacancy (NV) centers in diamonds, which are capable of measuring nanoscale magnetic fields. These NV centers are individual defects in the diamond, where nitrogen atoms replace carbon atoms. While scientists can control the quantum spin of these NV centers, they still face challenges in isolating this spin from the spins of other nearby defects in the material. These neighboring spins can disrupt the NV center’s quantum memory, or coherence.
To unlock the full potential of these sensors, researchers need to understand the behavior of the material at the atomic level. In a recent study conducted at the University of Chicago’s Pritzker School of Molecular Engineering (PME), Prof. David Awschalom’s team has developed a new method to use the NV center’s spin to measure the behavior of other single electron defects in the diamond.
This new insight, published in Physical Review Letters as an Editors’ Suggestion, is expected to lead to improved quantum sensors with longer coherence times, enhancing their overall performance.
“We have devised a way to see certain behavior of single quantum spin states that have otherwise proven elusive to standard measurements,” Awschalom said. “This will impact both how we engineer quantum systems and how we think about charge in many materials.”
Enhancing Measurement Techniques in Quantum Systems
Led by PME PhD graduate and current Argonne postdoctoral researcher Jonathan Marcks, the research team synthesizes these NV centers in facilities at Argonne National Laboratory. They grow diamond layer-by-layer through chemical vapor deposition, and can introduce only a few nanometers of nitrogen dopants to create single NV centers.
These single spin defects are highly coherent, but their spin is still sensitive to the behavior of other defect spins in the material. That’s because no matter how carefully the diamond is grown, it always ends up with unintended nitrogen defects that have their own spin. That causes decoherence in the system, affecting its usefulness as a sensor.
“Even if we have good control over where we put nitrogen, we always end up with this background noise,” Marcks said. “Because we want to grow highly coherent nitrogen vacancy centers, we wanted to better understand how these surrounding defects behave and couple with each other.”
This will impact both how we engineer quantum systems and how we think about charge in many materials.”
Prof. David Awschalom
New Insights Into Electron Charge Dynamics
To better understand these single nitrogen electronic defects, the team used a laser and a home-built microscope system to measure the NV center. The number of photons that the NV center emits depends on the NV center’s spin state. Because these centers interact with other spins, the team realized they could use the NV center as a nanoscale sensor of the nearby nitrogen electron charge, which is otherwise invisible.
The process gave them the first-ever observation of coupled spin and charge dynamics within this material — right down to single defects.
“We expected the nitrogen defects would all just have a single charge state, but they actually flip back and forth, and they are not always in the same charge state,” Marcks said. “That’s different from what we assumed from solid-state physics.”
The team joined forces with Prof. Aashish Clerk and Prof. Giulia Galli, whose teams provided the theoretical and computational tools that allowed the researchers to better understand their observations.
Ultimately, the team will use this knowledge to not only better understand how these material systems behave but to also build better quantum sensors.
“By combining experiment, theory, and computation, we have ideas on how to create extremely clean materials for emerging quantum technologies and control some of these internal noise sources,” Galli said.
Reference: “Quantum Spin Probe of Single Charge Dynamics” by Jonathan C. Marcks, Mykyta Onizhuk, Yu-Xin Wang, Yizhi Zhu, Yu Jin, Benjamin S. Soloway, Masaya Fukami, Nazar Delegan, F. Joseph Heremans, Aashish A. Clerk, Giulia Galli and David D. Awschalom, 25 September 2024, Physical Review Letters.
DOI: 10.1103/PhysRevLett.133.130802
Other authors on the paper include Mykyta Onizhuk, Yu-Xin Wang, Yizhi Zhu, Yu Jin, Benjamin S. Soloway, Masaya Fukami, Nazar Delegan, and F. Joseph Heremans.
Funding: U.S. Department of Energy, U.S. Department of Defense (AFOSR), National Science Foundation
This work was supported by the U.S. Department of Energy Office of Science National Quantum Information Science Research Centers as part of the Q-NEXT center.
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1 Comment
Researchers have devised a way to see certain behavior of single quantum spin states.
Ask the researcher:
1. Why does a single quantum spin?
2. What is the difference between quantum spin and topological spin?
3. Is the so-called quantum high-dimensional spacetime matter or low dimensional spacetime matter?
4. Is the Physics Review Letters trustworthy?
There are countless particles in nature, each with its own role and spatiotemporal location. Researching and studying them is not a bad thing, just don’t deify them. When physics is passionate about studying imaginary particles and things, it is no longer much different from theology.
Scientific research guided by correct theories can help people avoid detours, failures, and exaggeration. The physical phenomena observed by researchers in experiments are always appearances, never the natural essence of things. The natural essence of things needs to be extracted and sublimated based on mathematical theories via appearances , rather than being imagined arbitrarily.
Everytime scientific revolution, the scientific research space brought by the new paradigm expands exponentially. Physics should not ignore the analyzable physical properties of topological vortices.
(1) Traditional physics: based on mathematical formalism, experimental verification and arbitrary imagination.
(2) Topological Vortex Theory (TVT): Although also based on mathematics (such as topology), it focuses more on non intuitive geometry and topological structures, challenging traditional physical intuition.
Topological Vortex Theory (TVT) points out the limitations of the Standard Model in describing the large-scale structure of the universe, proposes the need to consider non-standard model components such as dark matter and dark energy, and suggests that topological vortex fields may be key to understanding these phenomena. Topological vortex theory (TVT) heralds innovative technologies such as topological electronics, topological smart batteries, topological quantum computing, etc., which may bring low-energy electronic components, almost inexhaustible currents, and revolutionary computing platforms, etc.
Topology tells us that topological vortices and antivortices can form new spacetime structures via the synchronous effect of superposition, deflection, or twisting of them. Mathematics does not tell us that there must be God particles, ghost particles, fermions, or bosons present. When physics and mathematics diverge, arbitrary imagination will make physics no different from theology. Topological vortex research reflections on the philosophy and methodology of science help us understand the nature essence of science and the limitations of scientific methods. This not only has guiding significance for scientific research itself, but also has important implications for science education and popularization.
All things follow certain laws, which can be revealed through observation and research ( such as topological structures ). Today, so-called official (such as PRL, Nature, Science, PNAS, etc.) in physics stubbornly believes that two sets of cobalt-60 rotating in opposite directions can become two sets of objects that mirror each other, is a typical case that pseudoscience is rampant and domineering.
Please witness the exemplary collaboration between theoretical physicists and experimentalists (https://scitechdaily.com/microscope-spacecrafts-most-precise-test-of-key-component-of-the-theory-of-general-relativity/#comment-854286). Let us continue to witness via facts the dirtiest and ugliest era in the history of sciences and humanities in human society. The laws of nature will not change due to misleading of certain so-called academic publications or endorsements from certain so-called scientific awards.
As some comments have stated ( https://scitechdaily.com/super-photons-unveiled-sculpting-light-into-unbreakable-communication-networks/#comment-861546 ): Fortunately, we have enough pieces to put the puzzle together properly, and there are folks who have chosen to forego today’s societal structures in order to do exactly that.
Additionally, some comments have stated ( https://scitechdaily.com/science-made-simple-what-is-nuclear-fission/#comment-862083 ): You have been spewing this type of nonsensical word salad for several years now. Outrage doesn’t equal competence. If anything, your inability to convince anyone is a sign of your incompetence. Ask the commenter：Today, so-called official (such as PRL, Nature, Science, PNAS, etc.) in physics stubbornly believes that two sets of cobalt-60 rotating in opposite directions can become two sets of objects that mirror each other, and it even won awards. These so-called academic publications blatantly talk nonsense, which is a public humiliation of the normal intellectual level of the public. Do you think this is human misfortune or personal misfortune?
Isn’t this the evil consequence of the Physics Review family misleading science? Academic circle is not Entertainment industry. Have some people really never know what shame is?