{"title":"From barrel to bottle","authors":"Stefanie Reichert","doi":"10.1038/s41567-024-02606-w","DOIUrl":"10.1038/s41567-024-02606-w","url":null,"abstract":"Measurements pervade winemaking, from the size of vineyards to the taste in your mouth. Stefanie Reichert gives us the tour.","PeriodicalId":19100,"journal":{"name":"Nature Physics","volume":"20 8","pages":"1360-1360"},"PeriodicalIF":17.6,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141973887","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 : 2024-08-12DOI: 10.1038/s41567-024-02608-8
Chiu Fan Lee
Migrating cell clusters exhibit finger-like protrusions at the front, attributed to leader cells physically dragging follower cells along. Now, an optogenetics experiment has shown that follower cells must also play a role in protrusion formation.
{"title":"It takes more than forceful leaders","authors":"Chiu Fan Lee","doi":"10.1038/s41567-024-02608-8","DOIUrl":"10.1038/s41567-024-02608-8","url":null,"abstract":"Migrating cell clusters exhibit finger-like protrusions at the front, attributed to leader cells physically dragging follower cells along. Now, an optogenetics experiment has shown that follower cells must also play a role in protrusion formation.","PeriodicalId":19100,"journal":{"name":"Nature Physics","volume":"20 10","pages":"1532-1533"},"PeriodicalIF":17.6,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141918808","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 : 2024-08-12DOI: 10.1038/s41567-024-02611-z
Julian F. Wienand, Simon Karch, Alexander Impertro, Christian Schweizer, Ewan McCulloch, Romain Vasseur, Sarang Gopalakrishnan, Monika Aidelsburger, Immanuel Bloch
A fundamental principle of chaotic quantum dynamics is that local subsystems eventually approach a thermal equilibrium state. The corresponding timescales increase with subsystem size as equilibration is limited by the hydrodynamic build-up of fluctuations on extended length scales. We perform large-scale quantum simulations that monitor particle-number fluctuations in tunable ladders of hard-core bosons and explore how the build-up of fluctuations changes as the system crosses over from integrable to fully chaotic dynamics. Our results indicate that the growth of large-scale fluctuations in chaotic, far-from-equilibrium systems is quantitatively determined by equilibrium transport coefficients, in agreement with the predictions of fluctuating hydrodynamics. This emergent hydrodynamic behaviour of subsystem fluctuations provides a test of fluctuation–dissipation relations far from equilibrium and allows the accurate determination of equilibrium transport coefficients using far-from-equilibrium quantum dynamics. Fluctuating hydrodynamics posits that thermalization in non-equilibrium systems depends on equilibrium transport coefficients. This hypothesis is now tested by exploring the emergence of fluctuations in non-equilibrium dynamics of ultracold atoms.
{"title":"Emergence of fluctuating hydrodynamics in chaotic quantum systems","authors":"Julian F. Wienand, Simon Karch, Alexander Impertro, Christian Schweizer, Ewan McCulloch, Romain Vasseur, Sarang Gopalakrishnan, Monika Aidelsburger, Immanuel Bloch","doi":"10.1038/s41567-024-02611-z","DOIUrl":"10.1038/s41567-024-02611-z","url":null,"abstract":"A fundamental principle of chaotic quantum dynamics is that local subsystems eventually approach a thermal equilibrium state. The corresponding timescales increase with subsystem size as equilibration is limited by the hydrodynamic build-up of fluctuations on extended length scales. We perform large-scale quantum simulations that monitor particle-number fluctuations in tunable ladders of hard-core bosons and explore how the build-up of fluctuations changes as the system crosses over from integrable to fully chaotic dynamics. Our results indicate that the growth of large-scale fluctuations in chaotic, far-from-equilibrium systems is quantitatively determined by equilibrium transport coefficients, in agreement with the predictions of fluctuating hydrodynamics. This emergent hydrodynamic behaviour of subsystem fluctuations provides a test of fluctuation–dissipation relations far from equilibrium and allows the accurate determination of equilibrium transport coefficients using far-from-equilibrium quantum dynamics. Fluctuating hydrodynamics posits that thermalization in non-equilibrium systems depends on equilibrium transport coefficients. This hypothesis is now tested by exploring the emergence of fluctuations in non-equilibrium dynamics of ultracold atoms.","PeriodicalId":19100,"journal":{"name":"Nature Physics","volume":"20 11","pages":"1732-1737"},"PeriodicalIF":17.6,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41567-024-02611-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141918812","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 : 2024-08-12DOI: 10.1038/s41567-024-02610-0
Jordi Tura
Recent experimental claims of quantum advantage rely on the absence of classical algorithms that can reproduce the results. A tensor network algorithm can now challenge recent optical quantum advantage experiments.
{"title":"Photon losses create tension for Gaussian boson sampling","authors":"Jordi Tura","doi":"10.1038/s41567-024-02610-0","DOIUrl":"10.1038/s41567-024-02610-0","url":null,"abstract":"Recent experimental claims of quantum advantage rely on the absence of classical algorithms that can reproduce the results. A tensor network algorithm can now challenge recent optical quantum advantage experiments.","PeriodicalId":19100,"journal":{"name":"Nature Physics","volume":"20 9","pages":"1371-1372"},"PeriodicalIF":17.6,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141918810","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 : 2024-08-12DOI: 10.1038/s41567-024-02600-2
Leone Rossetti, Steffen Grosser, Juan Francisco Abenza, Léo Valon, Pere Roca-Cusachs, Ricard Alert, Xavier Trepat
During development, wound healing and cancer invasion, migrating cell clusters feature highly protrusive leader cells at their front. Leader cells are thought to pull and direct their cohort of followers, but whether their local action is enough to guide the entire cluster, or if a global mechanical organization is needed, remains controversial. Here we show that the effectiveness of the leader–follower organization is proportional to the asymmetry of traction and tension within cell clusters. By combining hydrogel micropatterning and optogenetic activation, we generate highly protrusive leaders at the edge of minimal cell clusters. We find that the induced leader can robustly drag one follower but not larger groups. By measuring traction forces and tension propagation in clusters of increasing size, we establish a quantitative relationship between group velocity and the asymmetry of the traction and tension profiles. Modelling motile clusters as active polar fluids, we explain this force–velocity relationship in terms of asymmetries in the active traction profile. Our results challenge the notion of autonomous leader cells, showing that collective cell migration requires global mechanical organization within the cluster. Leader cells play an important role in guiding migratory clusters in various biological processes. Now, the mechanical organization of leader and followers within a cell cluster is shown to enable collective migration.
{"title":"Optogenetic generation of leader cells reveals a force–velocity relation for collective cell migration","authors":"Leone Rossetti, Steffen Grosser, Juan Francisco Abenza, Léo Valon, Pere Roca-Cusachs, Ricard Alert, Xavier Trepat","doi":"10.1038/s41567-024-02600-2","DOIUrl":"10.1038/s41567-024-02600-2","url":null,"abstract":"During development, wound healing and cancer invasion, migrating cell clusters feature highly protrusive leader cells at their front. Leader cells are thought to pull and direct their cohort of followers, but whether their local action is enough to guide the entire cluster, or if a global mechanical organization is needed, remains controversial. Here we show that the effectiveness of the leader–follower organization is proportional to the asymmetry of traction and tension within cell clusters. By combining hydrogel micropatterning and optogenetic activation, we generate highly protrusive leaders at the edge of minimal cell clusters. We find that the induced leader can robustly drag one follower but not larger groups. By measuring traction forces and tension propagation in clusters of increasing size, we establish a quantitative relationship between group velocity and the asymmetry of the traction and tension profiles. Modelling motile clusters as active polar fluids, we explain this force–velocity relationship in terms of asymmetries in the active traction profile. Our results challenge the notion of autonomous leader cells, showing that collective cell migration requires global mechanical organization within the cluster. Leader cells play an important role in guiding migratory clusters in various biological processes. Now, the mechanical organization of leader and followers within a cell cluster is shown to enable collective migration.","PeriodicalId":19100,"journal":{"name":"Nature Physics","volume":"20 10","pages":"1659-1669"},"PeriodicalIF":17.6,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141918809","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 : 2024-08-12DOI: 10.1038/s41567-024-02597-8
Christian Vanhille-Campos, Kevin D. Whitley, Philipp Radler, Martin Loose, Séamus Holden, Anđela Šarić
Filaments in the cell commonly treadmill. Driven by energy consumption, they grow on one end while shrinking on the other, causing filaments to appear motile even though individual proteins remain static. This process is characteristic of cytoskeletal filaments and leads to collective filament self-organization. Here we show that treadmilling drives filament nematic ordering by dissolving misaligned filaments. Taking the bacterial FtsZ protein involved in cell division as an example, we show that this mechanism aligns FtsZ filaments in vitro and drives the organization of the division ring in living Bacillus subtilis cells. We find that ordering via local dissolution also allows the system to quickly respond to chemical and geometrical biases in the cell, enabling us to quantitatively explain the ring formation dynamics in vivo. Beyond FtsZ and other cytoskeletal filaments, our study identifies a mechanism for self-organization via constant birth and death of energy-consuming filaments. Treadmilling of cytoskeletal filaments is crucial for their functional self-organization. Now the mechanism underpinning this collective organization is shown to be the dissolution of misaligned filaments.
{"title":"Self-organization of mortal filaments and its role in bacterial division ring formation","authors":"Christian Vanhille-Campos, Kevin D. Whitley, Philipp Radler, Martin Loose, Séamus Holden, Anđela Šarić","doi":"10.1038/s41567-024-02597-8","DOIUrl":"10.1038/s41567-024-02597-8","url":null,"abstract":"Filaments in the cell commonly treadmill. Driven by energy consumption, they grow on one end while shrinking on the other, causing filaments to appear motile even though individual proteins remain static. This process is characteristic of cytoskeletal filaments and leads to collective filament self-organization. Here we show that treadmilling drives filament nematic ordering by dissolving misaligned filaments. Taking the bacterial FtsZ protein involved in cell division as an example, we show that this mechanism aligns FtsZ filaments in vitro and drives the organization of the division ring in living Bacillus subtilis cells. We find that ordering via local dissolution also allows the system to quickly respond to chemical and geometrical biases in the cell, enabling us to quantitatively explain the ring formation dynamics in vivo. Beyond FtsZ and other cytoskeletal filaments, our study identifies a mechanism for self-organization via constant birth and death of energy-consuming filaments. Treadmilling of cytoskeletal filaments is crucial for their functional self-organization. Now the mechanism underpinning this collective organization is shown to be the dissolution of misaligned filaments.","PeriodicalId":19100,"journal":{"name":"Nature Physics","volume":"20 10","pages":"1670-1678"},"PeriodicalIF":17.6,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41567-024-02597-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141918811","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 : 2024-08-12DOI: 10.1038/s41567-024-02613-x
C. G. L. Bøttcher, N. R. Poniatowski, A. Grankin, M. E. Wesson, Z. Yan, U. Vool, V. M. Galitski, A. Yacoby
Hybrid systems represent one of the frontiers in the study of unconventional superconductivity and are a promising platform to realize topological superconducting states. These materials are challenging to probe using many conventional measurement techniques because of their mesoscopic dimensions, and therefore require new experimental probes so that they can be successfully characterized. Here, we demonstrate a probe that enables us to measure the superfluid density of micrometre-size superconductors using microwave techniques drawn from circuit quantum electrodynamics. We apply this technique to a superconductor–ferromagnet bilayer and find that the proximity-induced superfluid density is two-fold anisotropic within the plane of the sample. It also exhibits power-law temperature scaling that is indicative of a nodal superconducting state. These experimental results are consistent with the theoretically predicted signatures of induced triplet pairing with a nodal p-wave order parameter. Moreover, we observe modifications to the microwave response at frequencies near the ferromagnetic resonance, suggesting a coupling between the spin dynamics and induced superconducting order in the ferromagnetic layer. Our experimental technique can be employed more widely, for example to study fragile unconventional superconductivity in low-dimensional materials such as van der Waals heterostructures. Heterostructures of ferromagnets and superconductors may host exotic superconducting states. Now a circuit quantum electrodynamics technique is demonstrated that provides evidence for triplet p-wave pairing in such a heterostructure.
混合系统是非常规超导研究的前沿领域之一，也是实现拓扑超导态的前景广阔的平台。由于这些材料的介观尺寸，使用许多传统测量技术对它们进行探测具有挑战性，因此需要新的实验探针才能成功表征它们。在这里，我们展示了一种探针，它能让我们利用电路量子电动力学的微波技术测量微米级超导体的超流体密度。我们将这一技术应用于超导体-铁磁体双层膜，并发现在样品平面内，近距离诱导的超流体密度是两倍各向异性的。它还表现出幂律温度缩放，表明了结点超导状态。这些实验结果与理论预测的具有结点 p 波阶参数的诱导三重配对特征一致。此外，我们还观察到微波响应在铁磁共振频率附近的变化，这表明自旋动力学与铁磁层中的诱导超导阶之间存在耦合。我们的实验技术可以被更广泛地应用，例如研究范德华异质结构等低维材料中脆弱的非常规超导性。
{"title":"Circuit quantum electrodynamics detection of induced two-fold anisotropic pairing in a hybrid superconductor–ferromagnet bilayer","authors":"C. G. L. Bøttcher, N. R. Poniatowski, A. Grankin, M. E. Wesson, Z. Yan, U. Vool, V. M. Galitski, A. Yacoby","doi":"10.1038/s41567-024-02613-x","DOIUrl":"10.1038/s41567-024-02613-x","url":null,"abstract":"Hybrid systems represent one of the frontiers in the study of unconventional superconductivity and are a promising platform to realize topological superconducting states. These materials are challenging to probe using many conventional measurement techniques because of their mesoscopic dimensions, and therefore require new experimental probes so that they can be successfully characterized. Here, we demonstrate a probe that enables us to measure the superfluid density of micrometre-size superconductors using microwave techniques drawn from circuit quantum electrodynamics. We apply this technique to a superconductor–ferromagnet bilayer and find that the proximity-induced superfluid density is two-fold anisotropic within the plane of the sample. It also exhibits power-law temperature scaling that is indicative of a nodal superconducting state. These experimental results are consistent with the theoretically predicted signatures of induced triplet pairing with a nodal p-wave order parameter. Moreover, we observe modifications to the microwave response at frequencies near the ferromagnetic resonance, suggesting a coupling between the spin dynamics and induced superconducting order in the ferromagnetic layer. Our experimental technique can be employed more widely, for example to study fragile unconventional superconductivity in low-dimensional materials such as van der Waals heterostructures. Heterostructures of ferromagnets and superconductors may host exotic superconducting states. Now a circuit quantum electrodynamics technique is demonstrated that provides evidence for triplet p-wave pairing in such a heterostructure.","PeriodicalId":19100,"journal":{"name":"Nature Physics","volume":"20 10","pages":"1609-1615"},"PeriodicalIF":17.6,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41567-024-02613-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141918764","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 : 2024-08-08DOI: 10.1038/s41567-024-02605-x
Klemens Hammerer, Naceur Gaaloul
An atom interferometer now maintains a spatial superposition state for 70 seconds, compared to few seconds in freely falling systems. This could improve measurements of the strength of gravitational fields and quantum gravity studies.
{"title":"Matter waves hang in there","authors":"Klemens Hammerer, Naceur Gaaloul","doi":"10.1038/s41567-024-02605-x","DOIUrl":"10.1038/s41567-024-02605-x","url":null,"abstract":"An atom interferometer now maintains a spatial superposition state for 70 seconds, compared to few seconds in freely falling systems. This could improve measurements of the strength of gravitational fields and quantum gravity studies.","PeriodicalId":19100,"journal":{"name":"Nature Physics","volume":"20 8","pages":"1221-1222"},"PeriodicalIF":17.6,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141904516","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 : 2024-08-08DOI: 10.1038/s41567-024-02594-x
A bright, ultrashort X-ray pulse is used to transiently create and characterize warm dense copper. As the pulse intensity is increased, the opacity of copper is strongly altered. The recorded X-ray absorption spectra, substantiated by a theoretical electronic structure model, provide insight into the non-equilibrium electron dynamics during the formation of warm dense matter.
利用明亮的超短 X 射线脉冲瞬时产生并描述暖致密铜。随着脉冲强度的增加，铜的不透明度发生了强烈变化。所记录的 X 射线吸收光谱得到了理论电子结构模型的证实，使人们得以深入了解暖致密物质形成过程中的非平衡电子动力学。
{"title":"Nonlinear absorption of an X-ray pulse during the formation of warm dense matter","authors":"","doi":"10.1038/s41567-024-02594-x","DOIUrl":"10.1038/s41567-024-02594-x","url":null,"abstract":"A bright, ultrashort X-ray pulse is used to transiently create and characterize warm dense copper. As the pulse intensity is increased, the opacity of copper is strongly altered. The recorded X-ray absorption spectra, substantiated by a theoretical electronic structure model, provide insight into the non-equilibrium electron dynamics during the formation of warm dense matter.","PeriodicalId":19100,"journal":{"name":"Nature Physics","volume":"20 10","pages":"1536-1537"},"PeriodicalIF":17.6,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141904517","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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