New research at Harvard has enhanced quantum sensors’ capabilities through spin squeezing, a method that fine-tunes measurement sensitivity.
This breakthrough could lead to significant improvements in technologies ranging from biomedical imaging to atomic clocks.
Exploring Quantum Sensing Breakthroughs
Measurement is fundamental to every achievement and discovery in science. Today, thanks to advancements in quantum sensing, scientists can now measure phenomena that were once unimaginable—such as the vibrations of atoms, the properties of individual photons, and the subtle fluctuations associated with gravitational waves.
One promising quantum technique, known as “spin squeezing,” has the potential to greatly enhance the precision of quantum sensors. However, it has been notoriously difficult to achieve. In new research, Harvard physicists have brought spin squeezing closer to practical use.
Spin squeezing is a form of quantum entanglement that limits how much a group of particles can fluctuate. This restriction allows for more precise measurements of certain signals, although it comes at the cost of reduced accuracy for other complementary measurements. It’s similar to squeezing a balloon—gaining height by losing width.
Enhancing Measurement Precision Through Quantum Mechanics
“Quantum mechanics can enhance our ability to measure very small signals,” said Norman Yao, a physics professor and author of the new paper on spin squeezing in Nature Physics. “We have shown that it is possible to get such quantum-enhanced metrology in a much broader class of systems than was previously thought.”
In the balloon metaphor, a circle represents the uncertainty intrinsic to any quantum measurement, explained Maxwell Block, co-author of the paper and a former Griffin Graduate School of Arts and Sciences student. “By squeezing this uncertainty, making the balloon more like an ellipse, one can reshape the sensitivity of measurements,” Block said. “This means that certain measurements can be more precise than anything one could possibly do without quantum mechanics.”
An analog of spin squeezing was used, for example, to increase the sensitivity of the Nobel-garnering gravitational wave detectors in the LIGO experiment.
New Strategies for Quantum Enhancements
The Harvard team’s work built upon a landmark 1993 paper that first described the possibility of a spin-squeezed, entangled state brought about by “all-to-all” interactions between atoms. Such interactions are akin to a large Zoom meeting, in which each participant is interacting with every other participant at once. Between atoms, this type of connectivity easily enables the build-up of the quantum mechanical correlations necessary to induce a spin-squeezed state. However, in nature, atoms typically interact in a way that’s more like a game of telephone, only speaking with a few neighbors at a time.
“For years, it has been thought that one can only get truly quantum-enhanced spin squeezing via all-to-all interactions,” said Bingtian Ye, co-lead author of the paper and also a former Griffin Graduate School of Arts and Sciences student. “But what we have shown is that it is actually way easier.”
In their paper, the researchers outline a new strategy for generating spin-squeezed entanglement. They intuited, and together with collaborators in France quickly confirmed via experiment that the ingredients for spin squeezing are present in a ubiquitous type of magnetism found often in nature — ferromagnetism, which is also the force that makes refrigerator magnets stick. They posit that all-to-all interactions are not necessary to achieve spin squeezing, but rather, so long as the spins are connected well enough to sync into a magnetic state, they should also be able to dynamically generate spin squeezing.
Future Directions in Quantum Sensing
The researchers are optimistic that by thus lowering the barrier to spin squeezing, their work will inspire new ways for quantum scientists and engineers to create more portable sensors, useful in biomedical imaging, atomic clocks, and more.
In that spirit, Yao is now leading experiments to generate spin-squeezing in quantum sensors made out of nitrogen-vacancy centers, which are a type of defect in the crystal structure of diamond that have long been recognized as ideal quantum sensors.
Reference: “Scalable spin squeezing from finite-temperature easy-plane magnetism” by Maxwell Block, Bingtian Ye, Brenden Roberts, Sabrina Chern, Weijie Wu, Zilin Wang, Lode Pollet, Emily J. Davis, Bertrand I. Halperin and Norman Y. Yao, 29 July 2024, Nature Physics.
DOI: 10.1038/s41567-024-02562-5
The research received federal support from: the Army Research Office, the Office of Naval Research, the Department of Energy, the Department of Defense, and the National Science Foundation.
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4 Comments
Harvard’s Spin Squeezing Enhances Quantum Sensing. Unless it is pseudoscience, science never worries about being criticized.
The previous comments have been deleted. Ask the researchers:
1. What is the relationship between spin and quantum sensing?
2. Is spin related to topological vortices in nature?
3. Are the hypothetical particles (including so-called Quantum ) high-dimensional spacetime matter or low dimensional spacetime matter?
4. Is topological vortex high-dimensional spacetime matter or low dimensional spacetime matter?
5. Can low dimensional spacetime matter be the understructure of high-dimensional spacetime matter?
6. Which is easier to understand, topological materials or so-called quantum materials?
7. Is quantum material a topological material?
8. How do you understand the cat in quantum mechanics that is both dead and alive?
9. Is the topological vortex left-handed or right-handed?
10. Is the spacetime vortex a fact?
11. Which is easier to understand, topological vortex gravity or quantum gravity?
12. Doesn’t physics want a unified standard for basic materials?
and so on.
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). It is normal to make mistakes in scientific research, but what is abnormal is to stubbornly adhere to erroneous positions and not repent.
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?
Some people don’t have to worry. If you delete or prevent the comments from popping up, others will never know. The author never believes that fighting against rampant pseudoscience is an extremely easy task.
If someone feels ashamed and worried, it may not necessarily be a bad thing.
No matter what comments, they should be posted. Allowing the public to appreciate the various forms of sentient beings is also a source of endless joy. The author appreciates well founded criticism and comments.
If you delete the comments here, will others never know about these things?
Some scholars and so-called academic publications, even if they take off their fig leaf, will not feel ashamed.