Pub Date : 2024-11-11DOI: 10.1038/s41567-024-02656-0
Y. Maeno, A. Ikeda, G. Mattoni
Superconductivity in Sr2RuO4 was discovered 30 years ago. Among the many intriguing aspects of this unconventional superconductor is the picture of spin-triplet superconductivity, which could potentially carry both charge and spin supercurrents. This proposal was considered for a long time but was ultimately disproven in 2019. Despite intense research over the past several years, the superconducting symmetry of the archetypal unconventional superconductor Sr2RuO4 remains unresolved. Here we highlight the recent controversies and give a perspective of how the final resolution may be reached. After 30 years of extensive research, the nature of the unconventional superconductivity in Sr2RuO4 is still not fully understood. This Perspective summarizes the controversies surrounding this and discusses future research.
{"title":"Thirty years of puzzling superconductivity in Sr2RuO4","authors":"Y. Maeno, A. Ikeda, G. Mattoni","doi":"10.1038/s41567-024-02656-0","DOIUrl":"10.1038/s41567-024-02656-0","url":null,"abstract":"Superconductivity in Sr2RuO4 was discovered 30 years ago. Among the many intriguing aspects of this unconventional superconductor is the picture of spin-triplet superconductivity, which could potentially carry both charge and spin supercurrents. This proposal was considered for a long time but was ultimately disproven in 2019. Despite intense research over the past several years, the superconducting symmetry of the archetypal unconventional superconductor Sr2RuO4 remains unresolved. Here we highlight the recent controversies and give a perspective of how the final resolution may be reached. After 30 years of extensive research, the nature of the unconventional superconductivity in Sr2RuO4 is still not fully understood. This Perspective summarizes the controversies surrounding this and discusses future research.","PeriodicalId":19100,"journal":{"name":"Nature Physics","volume":"20 11","pages":"1712-1718"},"PeriodicalIF":17.6,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142598232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1038/s41567-024-02669-9
Michael J. Steel
Optical waveguides that route light are a core technology of modern photonics and the bedrock of the global communications network. A surprising diffusion mechanism for guiding light has now been identified, and it is strangely close to home.
{"title":"Diffusive light pipes","authors":"Michael J. Steel","doi":"10.1038/s41567-024-02669-9","DOIUrl":"10.1038/s41567-024-02669-9","url":null,"abstract":"Optical waveguides that route light are a core technology of modern photonics and the bedrock of the global communications network. A surprising diffusion mechanism for guiding light has now been identified, and it is strangely close to home.","PeriodicalId":19100,"journal":{"name":"Nature Physics","volume":"20 12","pages":"1853-1854"},"PeriodicalIF":17.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1038/s41567-024-02667-x
Zejin Rao, Changhao Meng, Youcai Han, Liping Zhu, Kun Ding, Zhenghua An
A thorough understanding of the topological classifications of non-Hermitian energy bands is essential for advancing non-Hermitian band theory and its applications. As evidenced in various disciplines of physics, including optics, electronics and acoustics, the process of braiding plays a crucial role in the classification of non-Hermitian bands that manifest topological characteristics. Here we demonstrate topological braiding of both reflectionless states and resonant states in non-Hermitian magnons, unveiling a reversal in their braiding handedness. Furthermore, we constitute parity–time symmetric reflectionless scattering modes, along with their degenerate exceptional points. Our results not only underscore the importance of braided scattering states, but also establish magnonics as a versatile platform for exploring non-Hermitian band theory and developing magnon-based applications, including topological energy transfer, tunable absorbers and logic circuits. Extending topological braids of complex energy bands to non-Hermitian systems of magnons—the quanta of spin waves—is a crucial step in the development of spin-based topological devices. This has now been experimentally demonstrated.
{"title":"Braiding reflectionless states in non-Hermitian magnonics","authors":"Zejin Rao, Changhao Meng, Youcai Han, Liping Zhu, Kun Ding, Zhenghua An","doi":"10.1038/s41567-024-02667-x","DOIUrl":"10.1038/s41567-024-02667-x","url":null,"abstract":"A thorough understanding of the topological classifications of non-Hermitian energy bands is essential for advancing non-Hermitian band theory and its applications. As evidenced in various disciplines of physics, including optics, electronics and acoustics, the process of braiding plays a crucial role in the classification of non-Hermitian bands that manifest topological characteristics. Here we demonstrate topological braiding of both reflectionless states and resonant states in non-Hermitian magnons, unveiling a reversal in their braiding handedness. Furthermore, we constitute parity–time symmetric reflectionless scattering modes, along with their degenerate exceptional points. Our results not only underscore the importance of braided scattering states, but also establish magnonics as a versatile platform for exploring non-Hermitian band theory and developing magnon-based applications, including topological energy transfer, tunable absorbers and logic circuits. Extending topological braids of complex energy bands to non-Hermitian systems of magnons—the quanta of spin waves—is a crucial step in the development of spin-based topological devices. This has now been experimentally demonstrated.","PeriodicalId":19100,"journal":{"name":"Nature Physics","volume":"20 12","pages":"1904-1911"},"PeriodicalIF":17.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1038/s41567-024-02674-y
Haoxin Zhou
The ground state of electrons in charge-neutral graphene in a strong magnetic field has not been conclusively identified. Thermal transport measurements narrow down the possible candidates, with evidence that the ground state does not conduct heat.
{"title":"No heat flow in charge-neutral graphene","authors":"Haoxin Zhou","doi":"10.1038/s41567-024-02674-y","DOIUrl":"10.1038/s41567-024-02674-y","url":null,"abstract":"The ground state of electrons in charge-neutral graphene in a strong magnetic field has not been conclusively identified. Thermal transport measurements narrow down the possible candidates, with evidence that the ground state does not conduct heat.","PeriodicalId":19100,"journal":{"name":"Nature Physics","volume":"20 12","pages":"1849-1850"},"PeriodicalIF":17.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01Epub Date: 2022-03-09DOI: 10.1080/08869634.2022.2047511
Anna Alessandri Bonetti, Patrizia Gallenzi
Objective: To detect whether myotatic reflex activation of masticatory muscles during drug-induced sleep endoscopy (DISE) can be an indirect marker for temporomandibular disorder (TMD) in patients suffering from obstructive sleep apnea (OSA).
Methods: OSA patients were prospectively recruited and underwent a complete TMD examination prior to undergoing DISE with the addition of electrodes applied over masticatory muscles. A positive activation of myotatic reflex was considered in case of an increase in muscle tone of at least 50%.
Results: Of the 41 patients included, 48.8% presented activation of myotatic reflex. Of these patients, 45% presented a TMD diagnosis, 40% presented pain at masticatory muscles palpation, and 15% did not report pain during clinical examination.
Conclusion: An increase in EMG activity during mandibular advancement is not associated with TMD presence, but it can be an indirect marker of pain in the orofacial area in OSA patients.
{"title":"Is there an association between EMG activity and temporomandibular disorders during orthotic mandibular advancement in sleep apnea patients undergoing DISE?","authors":"Anna Alessandri Bonetti, Patrizia Gallenzi","doi":"10.1080/08869634.2022.2047511","DOIUrl":"10.1080/08869634.2022.2047511","url":null,"abstract":"<p><strong>Objective: </strong>To detect whether myotatic reflex activation of masticatory muscles during drug-induced sleep endoscopy (DISE) can be an indirect marker for temporomandibular disorder (TMD) in patients suffering from obstructive sleep apnea (OSA).</p><p><strong>Methods: </strong>OSA patients were prospectively recruited and underwent a complete TMD examination prior to undergoing DISE with the addition of electrodes applied over masticatory muscles. A positive activation of myotatic reflex was considered in case of an increase in muscle tone of at least 50%.</p><p><strong>Results: </strong>Of the 41 patients included, 48.8% presented activation of myotatic reflex. Of these patients, 45% presented a TMD diagnosis, 40% presented pain at masticatory muscles palpation, and 15% did not report pain during clinical examination.</p><p><strong>Conclusion: </strong>An increase in EMG activity during mandibular advancement is not associated with TMD presence, but it can be an indirect marker of pain in the orofacial area in OSA patients.</p>","PeriodicalId":19100,"journal":{"name":"Nature Physics","volume":"17 1","pages":"730-735"},"PeriodicalIF":2.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79528793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1038/s41567-024-02665-z
Kevin J. Mitchell, Vytautas Gradauskas, Jack Radford, Ilya Starshynov, Samuel Nerenberg, Ewan M. Wright, Daniele Faccio
The guiding and transport of energy, for example, of electromagnetic waves, underpins many modern technologies, ranging from long-distance optical fibre telecommunications to on-chip optical processors. Traditionally, a mechanism is required that exponentially localizes the waves or particles in the confinement region, such as total internal reflection at a boundary. Here we introduce a waveguiding mechanism that relies on a different origin for the exponential confinement and that arises owing to the physics of diffusion. We demonstrate this concept using light and show that the photon density can propagate as a guided mode along a core structure embedded in a scattering opaque material, enhancing light transmission by orders of magnitude and along non-trivial, such as curved, trajectories. This waveguiding mechanism can also occur naturally, for example, in the cerebrospinal fluid surrounding the brain and along tendons in the human body, and is to be expected in other systems that follow the same physics such as neutron diffusion. Waveguides—often based on total internal reflection—underpin many photonic technologies, including fibre networks for broadband communications. Now a different type of waveguide based on physical diffusion in a scattering medium is demonstrated.
{"title":"Energy transport in diffusive waveguides","authors":"Kevin J. Mitchell, Vytautas Gradauskas, Jack Radford, Ilya Starshynov, Samuel Nerenberg, Ewan M. Wright, Daniele Faccio","doi":"10.1038/s41567-024-02665-z","DOIUrl":"10.1038/s41567-024-02665-z","url":null,"abstract":"The guiding and transport of energy, for example, of electromagnetic waves, underpins many modern technologies, ranging from long-distance optical fibre telecommunications to on-chip optical processors. Traditionally, a mechanism is required that exponentially localizes the waves or particles in the confinement region, such as total internal reflection at a boundary. Here we introduce a waveguiding mechanism that relies on a different origin for the exponential confinement and that arises owing to the physics of diffusion. We demonstrate this concept using light and show that the photon density can propagate as a guided mode along a core structure embedded in a scattering opaque material, enhancing light transmission by orders of magnitude and along non-trivial, such as curved, trajectories. This waveguiding mechanism can also occur naturally, for example, in the cerebrospinal fluid surrounding the brain and along tendons in the human body, and is to be expected in other systems that follow the same physics such as neutron diffusion. Waveguides—often based on total internal reflection—underpin many photonic technologies, including fibre networks for broadband communications. Now a different type of waveguide based on physical diffusion in a scattering medium is demonstrated.","PeriodicalId":19100,"journal":{"name":"Nature Physics","volume":"20 12","pages":"1955-1959"},"PeriodicalIF":17.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41567-024-02665-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-31DOI: 10.1038/s41567-024-02671-1
Alicia J. Kollár
Superconducting qubits can be fabricated and controlled in large numbers, which makes them an appealing platform for quantum simulations of many-body physics. However, a scalable way of implementing electromagnetism has been lacking — until now.
{"title":"Superconducting circuits feel the pull of synthetic magnetism","authors":"Alicia J. Kollár","doi":"10.1038/s41567-024-02671-1","DOIUrl":"10.1038/s41567-024-02671-1","url":null,"abstract":"Superconducting qubits can be fabricated and controlled in large numbers, which makes them an appealing platform for quantum simulations of many-body physics. However, a scalable way of implementing electromagnetism has been lacking — until now.","PeriodicalId":19100,"journal":{"name":"Nature Physics","volume":"20 12","pages":"1859-1860"},"PeriodicalIF":17.6,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142556034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-30DOI: 10.1038/s41567-024-02661-3
Ilan T. Rosen, Sarah Muschinske, Cora N. Barrett, Arkya Chatterjee, Max Hays, Michael A. DeMarco, Amir H. Karamlou, David A. Rower, Rabindra Das, David K. Kim, Bethany M. Niedzielski, Meghan Schuldt, Kyle Serniak, Mollie E. Schwartz, Jonilyn L. Yoder, Jeffrey A. Grover, William D. Oliver
Superconducting quantum processors are a compelling platform for analogue quantum simulation due to the precision control, fast operation and site-resolved readout inherent to the hardware. Arrays of coupled superconducting qubits natively emulate the dynamics of interacting particles according to the Bose–Hubbard model. However, many interesting condensed-matter phenomena emerge only in the presence of electromagnetic fields. Here we emulate the dynamics of charged particles in an electromagnetic field using a superconducting quantum simulator. We realize a broadly adjustable synthetic magnetic vector potential by applying continuous modulation tones to all qubits. We verify that the synthetic vector potential obeys the required properties of electromagnetism: a spatially varying vector potential breaks time-reversal symmetry and generates a gauge-invariant synthetic magnetic field, and a temporally varying vector potential produces a synthetic electric field. We demonstrate that the Hall effect—the transverse deflection of a charged particle propagating in an electromagnetic field—exists in the presence of the synthetic electromagnetic field. Arrays of superconducting transmon qubits can be used to study the Bose–Hubbard model. Synthetic electromagnetic fields have now been added to this analogue quantum simulation platform.
{"title":"A synthetic magnetic vector potential in a 2D superconducting qubit array","authors":"Ilan T. Rosen, Sarah Muschinske, Cora N. Barrett, Arkya Chatterjee, Max Hays, Michael A. DeMarco, Amir H. Karamlou, David A. Rower, Rabindra Das, David K. Kim, Bethany M. Niedzielski, Meghan Schuldt, Kyle Serniak, Mollie E. Schwartz, Jonilyn L. Yoder, Jeffrey A. Grover, William D. Oliver","doi":"10.1038/s41567-024-02661-3","DOIUrl":"10.1038/s41567-024-02661-3","url":null,"abstract":"Superconducting quantum processors are a compelling platform for analogue quantum simulation due to the precision control, fast operation and site-resolved readout inherent to the hardware. Arrays of coupled superconducting qubits natively emulate the dynamics of interacting particles according to the Bose–Hubbard model. However, many interesting condensed-matter phenomena emerge only in the presence of electromagnetic fields. Here we emulate the dynamics of charged particles in an electromagnetic field using a superconducting quantum simulator. We realize a broadly adjustable synthetic magnetic vector potential by applying continuous modulation tones to all qubits. We verify that the synthetic vector potential obeys the required properties of electromagnetism: a spatially varying vector potential breaks time-reversal symmetry and generates a gauge-invariant synthetic magnetic field, and a temporally varying vector potential produces a synthetic electric field. We demonstrate that the Hall effect—the transverse deflection of a charged particle propagating in an electromagnetic field—exists in the presence of the synthetic electromagnetic field. Arrays of superconducting transmon qubits can be used to study the Bose–Hubbard model. Synthetic electromagnetic fields have now been added to this analogue quantum simulation platform.","PeriodicalId":19100,"journal":{"name":"Nature Physics","volume":"20 12","pages":"1881-1887"},"PeriodicalIF":17.6,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142541753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-29DOI: 10.1038/s41567-024-02685-9
Dawn Graninger
Nuclear explosives are the most promising method for steering a large asteroid away from Earth and mitigating an impact. Laboratory experiments with X-ray pulses have now mimicked such an event, demonstrating how efficient this technique is.
核爆炸是引导大型小行星远离地球并减轻撞击的最有希望的方法。利用 X 射线脉冲进行的实验室实验现在已经模拟了这种事件，证明了这种技术的高效性。
{"title":"A push for planetary defence","authors":"Dawn Graninger","doi":"10.1038/s41567-024-02685-9","DOIUrl":"10.1038/s41567-024-02685-9","url":null,"abstract":"Nuclear explosives are the most promising method for steering a large asteroid away from Earth and mitigating an impact. Laboratory experiments with X-ray pulses have now mimicked such an event, demonstrating how efficient this technique is.","PeriodicalId":19100,"journal":{"name":"Nature Physics","volume":"20 11","pages":"1706-1707"},"PeriodicalIF":17.6,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142520164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-29DOI: 10.1038/s41567-024-02672-0
R. Delagrange, M. Garg, G. Le Breton, A. Zhang, Q. Dong, Y. Jin, K. Watanabe, T. Taniguchi, P. Roulleau, O. Maillet, P. Roche, F. D. Parmentier
Undoped graphene is a gapless semiconductor; however, when placed under a high perpendicular magnetic field and cooled to low temperature, it develops an insulating state. This state, dubbed ν = 0, is due to the interplay between electronic interactions and the four-fold spin and valley degeneracies in the flat band formed by the n = 0 Landau level. The nature of the ground state of ν = 0, including its spin and valley polarization, is still under debate. Here we observe vanishing bulk thermal transport in monolayer at ν = 0, in contradiction with the expected ground state, which is predicted to have finite thermal conductance even at very low temperature. Our results highlight the need for further investigations on the nature of ν = 0. Charge-neutral graphene in the quantum Hall regime is known to be an insulator. Now thermal transport measurements show that it also does not conduct heat. This sheds light on the nature of the ground state in this regime.
{"title":"Vanishing bulk heat flow in the ν = 0 quantum Hall ferromagnet in monolayer graphene","authors":"R. Delagrange, M. Garg, G. Le Breton, A. Zhang, Q. Dong, Y. Jin, K. Watanabe, T. Taniguchi, P. Roulleau, O. Maillet, P. Roche, F. D. Parmentier","doi":"10.1038/s41567-024-02672-0","DOIUrl":"10.1038/s41567-024-02672-0","url":null,"abstract":"Undoped graphene is a gapless semiconductor; however, when placed under a high perpendicular magnetic field and cooled to low temperature, it develops an insulating state. This state, dubbed ν = 0, is due to the interplay between electronic interactions and the four-fold spin and valley degeneracies in the flat band formed by the n = 0 Landau level. The nature of the ground state of ν = 0, including its spin and valley polarization, is still under debate. Here we observe vanishing bulk thermal transport in monolayer at ν = 0, in contradiction with the expected ground state, which is predicted to have finite thermal conductance even at very low temperature. Our results highlight the need for further investigations on the nature of ν = 0. Charge-neutral graphene in the quantum Hall regime is known to be an insulator. Now thermal transport measurements show that it also does not conduct heat. This sheds light on the nature of the ground state in this regime.","PeriodicalId":19100,"journal":{"name":"Nature Physics","volume":"20 12","pages":"1927-1932"},"PeriodicalIF":17.6,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142520166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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