Ever since the discovery of high-temperature superconductivity in cuprates, gaining microscopic insights into the nature of pairing in strongly correlated systems has remained one of the greatest challenges in modern condensed matter physics. Following recent experiments reporting superconductivity in the bilayer nickelate La3Ni2O7 (LNO) with remarkably high critical temperatures of Tc = 80 K, it has been argued that the low-energy physics of LNO can be described by the strongly correlated, mixed-dimensional bilayer t–J model. Here we investigate this bilayer system and utilize density matrix renormalization group techniques to establish a thorough understanding of the model and the magnetically induced pairing through comparison to the perturbative limit of dominating inter-layer spin couplings. In particular, this allows us to explain appearing finite-size effects, firmly establishing the existence of long-range superconducting order in the thermodynamic limit. By analyzing binding energies, we predict a BEC–BCS crossover as a function of the Hamiltonian parameters. We find large binding energies of the order of the inter-layer coupling that suggest strikingly high critical temperatures of the Berezinskii–Kosterlitz–Thouless transition, raising the question of whether (mixD) bilayer superconductors possibly facilitate critical temperatures above room temperature. The authors study a minimal model to describe the physics of bilayer nickelates, a novel high-temperature superconductor. They find that the model features extraordinarily high critical temperatures for superconductivity, and gain a detailed understanding of the underlying physics through an intuitive perturbative limit.
{"title":"Superconductivity in the pressurized nickelate La3Ni2O7 in the vicinity of a BEC–BCS crossover","authors":"Henning Schlömer, Ulrich Schollwöck, Fabian Grusdt, Annabelle Bohrdt","doi":"10.1038/s42005-024-01854-9","DOIUrl":"10.1038/s42005-024-01854-9","url":null,"abstract":"Ever since the discovery of high-temperature superconductivity in cuprates, gaining microscopic insights into the nature of pairing in strongly correlated systems has remained one of the greatest challenges in modern condensed matter physics. Following recent experiments reporting superconductivity in the bilayer nickelate La3Ni2O7 (LNO) with remarkably high critical temperatures of Tc = 80 K, it has been argued that the low-energy physics of LNO can be described by the strongly correlated, mixed-dimensional bilayer t–J model. Here we investigate this bilayer system and utilize density matrix renormalization group techniques to establish a thorough understanding of the model and the magnetically induced pairing through comparison to the perturbative limit of dominating inter-layer spin couplings. In particular, this allows us to explain appearing finite-size effects, firmly establishing the existence of long-range superconducting order in the thermodynamic limit. By analyzing binding energies, we predict a BEC–BCS crossover as a function of the Hamiltonian parameters. We find large binding energies of the order of the inter-layer coupling that suggest strikingly high critical temperatures of the Berezinskii–Kosterlitz–Thouless transition, raising the question of whether (mixD) bilayer superconductors possibly facilitate critical temperatures above room temperature. The authors study a minimal model to describe the physics of bilayer nickelates, a novel high-temperature superconductor. They find that the model features extraordinarily high critical temperatures for superconductivity, and gain a detailed understanding of the underlying physics through an intuitive perturbative limit.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-8"},"PeriodicalIF":5.4,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01854-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142596163","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 : 2024-11-08DOI: 10.1038/s42005-024-01857-6
V. Sazgari, T. P. Ying, J. N. Graham, C. Mielke III, D. Das, S. S. Islam, S. Shin, M. Medarde, M. Bartkowiak, R. Khasanov, H. Luetkens, H. Hosono, Z. Guguchia
Vacancies in solid-state physics are underexplored in materials with strong electron-electron correlations. Recent research on the Ir-Sb binary system revealed an extended buckled-honeycomb vacancy (BHV) order. Superconductivity arises by suppressing BHV ordering through high-pressure growth with excess Ir atoms or Rh substitution, yet the superconducting pairing nature remains unknown. To explore this, we conducted muon spin rotation experiments on Ir1−δSb (synthesized at 5.5 GPa, Tc = 4.2 K) and ambient pressure synthesized optimally Rh-doped Ir1−xRhxSb (x=0.3, Tc = 2.7 K). The exponential temperature dependence of the superfluid density suggests a fully gapped superconducting state exists in both samples. The ratio of Tc to the superfluid density resembles that of unconventional superconductors. A significant increase in the superfluid density in the high-pressure synthesized sample correlates with Tc, indicating that unconventional superconductivity is intrinsic to the Ir-Sb binary system. These findings, along with the dome-shaped phase diagram, highlight IrSb as the first unconventional superconducting parent phase with ordered vacancies, requiring further theoretical investigations. Vacancies or defects are structural features of the crystal lattice that can be used to engineer the physical properties of a solid-state system, and have played an important role in the investigation of quantum materials. Here, the authors apply muon spin rotation to explore the suppression of vacancy ordering in Rh-doped Ir1−xRhxSb and discuss the potential presence of unconventional superconductivity in the system.
{"title":"Unveiling nodeless unconventional superconductivity proximate to honeycomb-vacancy ordering in the Ir-Sb binary system","authors":"V. Sazgari, T. P. Ying, J. N. Graham, C. Mielke III, D. Das, S. S. Islam, S. Shin, M. Medarde, M. Bartkowiak, R. Khasanov, H. Luetkens, H. Hosono, Z. Guguchia","doi":"10.1038/s42005-024-01857-6","DOIUrl":"10.1038/s42005-024-01857-6","url":null,"abstract":"Vacancies in solid-state physics are underexplored in materials with strong electron-electron correlations. Recent research on the Ir-Sb binary system revealed an extended buckled-honeycomb vacancy (BHV) order. Superconductivity arises by suppressing BHV ordering through high-pressure growth with excess Ir atoms or Rh substitution, yet the superconducting pairing nature remains unknown. To explore this, we conducted muon spin rotation experiments on Ir1−δSb (synthesized at 5.5 GPa, Tc = 4.2 K) and ambient pressure synthesized optimally Rh-doped Ir1−xRhxSb (x=0.3, Tc = 2.7 K). The exponential temperature dependence of the superfluid density suggests a fully gapped superconducting state exists in both samples. The ratio of Tc to the superfluid density resembles that of unconventional superconductors. A significant increase in the superfluid density in the high-pressure synthesized sample correlates with Tc, indicating that unconventional superconductivity is intrinsic to the Ir-Sb binary system. These findings, along with the dome-shaped phase diagram, highlight IrSb as the first unconventional superconducting parent phase with ordered vacancies, requiring further theoretical investigations. Vacancies or defects are structural features of the crystal lattice that can be used to engineer the physical properties of a solid-state system, and have played an important role in the investigation of quantum materials. Here, the authors apply muon spin rotation to explore the suppression of vacancy ordering in Rh-doped Ir1−xRhxSb and discuss the potential presence of unconventional superconductivity in the system.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-7"},"PeriodicalIF":5.4,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01857-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142596150","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 : 2024-11-07DOI: 10.1038/s42005-024-01852-x
Laura Budewig, Sang-Kil Son, Robin Santra
In an intense X-ray free-electron laser (XFEL) pulse, atoms are sequentially ionised by multiple X-ray photons. Photoionisation generally induces an alignment of the electron cloud of the produced atomic ion regarding its orbital-angular-momentum projections. However, how the alignment evolves during sequential X-ray multi-photon ionisation accompanied by decay processes has been unexplored. Here we present a theoretical prediction of the time evolution of the electron-cloud alignment of argon ions induced by XFEL pulses. To this end, we calculate state-resolved ionisation dynamics of atomic argon interacting with an intense linearly polarised X-ray pulse, which generates ions in a wide range of charge states with non-zero orbital- and spin-angular momenta. Employing time-resolved alignment parameters, we predict the existence of non-trivial alignment dynamics during intense XFEL pulses. This implies that even if initially the atomic electron cloud is perfectly spherically symmetric, X-ray multi-photon ionisation can lead to noticeable reshaping of the electron cloud. Single photoionisation can align an atomic electron cloud, yet it is unexplored how the alignment evolves during sequential multi-photon multiple ionisation induced by intense X-ray pulses. In their paper, the authors predict the existence of non-trivial electron-cloud alignment dynamics in quantum-state-resolved X-ray multi-photon ionisation.
在强 X 射线自由电子激光（XFEL）脉冲中，原子依次被多个 X 射线光子电离。光离子化通常会导致产生的原子离子的电子云在其轨道-角动量投影上发生排列。然而，在伴随衰变过程的连续 X 射线多光子电离过程中，排列是如何演变的还没有被研究。在此，我们对 XFEL 脉冲诱导的氩离子电子云排列的时间演变进行了理论预测。为此，我们计算了与强线性偏振 X 射线脉冲相互作用的原子氩的状态分辨电离动力学，该脉冲会产生具有非零轨道矩和自旋角矩的多种电荷态离子。利用时间分辨对齐参数，我们预测在强 XFEL 脉冲期间存在非三维对齐动力学。这意味着，即使原子电子云最初是完全球对称的，X射线多光子电离也会导致电子云的明显重塑。单光子电离可以使原子电子云排列整齐，但在强 X 射线脉冲诱导的连续多光子多重电离过程中，电子云的排列是如何演变的，这一点尚未得到研究。作者在论文中预测，在量子态分辨 X 射线多光子电离过程中，电子云对齐动力学存在非难性。
{"title":"Electron-cloud alignment dynamics induced by an intense X-ray free-electron laser pulse: a case study on atomic argon","authors":"Laura Budewig, Sang-Kil Son, Robin Santra","doi":"10.1038/s42005-024-01852-x","DOIUrl":"10.1038/s42005-024-01852-x","url":null,"abstract":"In an intense X-ray free-electron laser (XFEL) pulse, atoms are sequentially ionised by multiple X-ray photons. Photoionisation generally induces an alignment of the electron cloud of the produced atomic ion regarding its orbital-angular-momentum projections. However, how the alignment evolves during sequential X-ray multi-photon ionisation accompanied by decay processes has been unexplored. Here we present a theoretical prediction of the time evolution of the electron-cloud alignment of argon ions induced by XFEL pulses. To this end, we calculate state-resolved ionisation dynamics of atomic argon interacting with an intense linearly polarised X-ray pulse, which generates ions in a wide range of charge states with non-zero orbital- and spin-angular momenta. Employing time-resolved alignment parameters, we predict the existence of non-trivial alignment dynamics during intense XFEL pulses. This implies that even if initially the atomic electron cloud is perfectly spherically symmetric, X-ray multi-photon ionisation can lead to noticeable reshaping of the electron cloud. Single photoionisation can align an atomic electron cloud, yet it is unexplored how the alignment evolves during sequential multi-photon multiple ionisation induced by intense X-ray pulses. In their paper, the authors predict the existence of non-trivial electron-cloud alignment dynamics in quantum-state-resolved X-ray multi-photon ionisation.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-9"},"PeriodicalIF":5.4,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01852-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595697","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 : 2024-11-07DOI: 10.1038/s42005-024-01855-8
Grazia Di Bello, Andrea Ponticelli, Fabrizio Pavan, Vittorio Cataudella, Giulio De Filippis, Antonio de Candia, Carmine Antonio Perroni
Quantum states beyond thermodynamic equilibrium represent fascinating and cutting-edge research. However, the behavior of dynamical quantum phase transitions in complex open quantum systems remains poorly understood. Here, using state-of-the-art numerical approaches, we show that by quenching the qubits-oscillator coupling in a dissipative two-qubit Rabi model, the system undergoes dynamical quantum phase transitions. These transitions are characterized by kinks in the Loschmidt echo rate function at parameter values close to a thermodynamic quantum phase transition and are associated with distinct entanglement features. The two classes of critical phenomena depend on qubit interactions and entanglement, revealing different behaviors of the critical exponent of the first kink of the Loschmidt echo for interacting versus non-interacting qubits. This research enhances our understanding of non-equilibrium quantum systems and offers potential applications in quantum sensing and metrology, as it examines how dynamical transitions can enhance the sensitivity of the Loschmidt echo to the quench parameters. Dynamical quantum phase transitions can be observed when time is treated as a control parameter in non-equilibrium quantum systems. The authors show that quenching the qubits-oscillator coupling in a dissipative two-qubit system leads to different transitions depending on interactions and entanglement, with promising applications in quantum sensing and metrology.
{"title":"Environment induced dynamical quantum phase transitions in two-qubit Rabi model","authors":"Grazia Di Bello, Andrea Ponticelli, Fabrizio Pavan, Vittorio Cataudella, Giulio De Filippis, Antonio de Candia, Carmine Antonio Perroni","doi":"10.1038/s42005-024-01855-8","DOIUrl":"10.1038/s42005-024-01855-8","url":null,"abstract":"Quantum states beyond thermodynamic equilibrium represent fascinating and cutting-edge research. However, the behavior of dynamical quantum phase transitions in complex open quantum systems remains poorly understood. Here, using state-of-the-art numerical approaches, we show that by quenching the qubits-oscillator coupling in a dissipative two-qubit Rabi model, the system undergoes dynamical quantum phase transitions. These transitions are characterized by kinks in the Loschmidt echo rate function at parameter values close to a thermodynamic quantum phase transition and are associated with distinct entanglement features. The two classes of critical phenomena depend on qubit interactions and entanglement, revealing different behaviors of the critical exponent of the first kink of the Loschmidt echo for interacting versus non-interacting qubits. This research enhances our understanding of non-equilibrium quantum systems and offers potential applications in quantum sensing and metrology, as it examines how dynamical transitions can enhance the sensitivity of the Loschmidt echo to the quench parameters. Dynamical quantum phase transitions can be observed when time is treated as a control parameter in non-equilibrium quantum systems. The authors show that quenching the qubits-oscillator coupling in a dissipative two-qubit system leads to different transitions depending on interactions and entanglement, with promising applications in quantum sensing and metrology.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-11"},"PeriodicalIF":5.4,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01855-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595694","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 : 2024-11-06DOI: 10.1038/s42005-024-01856-7
Yuan-Zhi He, Chen-Sheng Ma, Hao Yin
The application of terahertz technology in space is frontier for the development of 6G technologies. Terahertz transceiver devices based on gallium arsenide Schottky barrier diodes (GaAs SBDs) have the characteristics of small size, light weight and low power consumption, making them suitable for application on spacecraft. However, there is currently a lack of experimental assessments on their space adaptability. Here, we study the radiation hardness of terahertz devices to determine their adaptability in complex space environments. We exposed GaAs SBDs and terahertz multipliers as typical terahertz devices to gamma rays and protons. The experimental results showed that the terahertz devices exhibited good tolerance to protons, but prolonged exposure to gamma rays could significantly increase the leakage current of the GaAs SBDs and alter its C-V characteristics, leading to the failure of the terahertz multiplier. Nevertheless, the terahertz devices maintained a good level of radiation hardness, making them highly suitable for use in Low Earth Orbit (LEO) satellites. The comparison between the results of proton and gamma ray tests indicated that the terahertz devices exhibited high inherent radiation hardness against displacement damage but were more sensitive to ionization damage, requiring higher shielding requirements. Terahertz technology holds tremendous potential for application in high-speed, high-capacity space communication missions, yet there currently exists a lack of research on the space adaptability of its key components. The authors have conducted radiation hardness testing of gallium arsenide terahertz devices through ground-based simulated irradiation experiments.
{"title":"Measuring the radiation hardness of terahertz devices for space applications","authors":"Yuan-Zhi He, Chen-Sheng Ma, Hao Yin","doi":"10.1038/s42005-024-01856-7","DOIUrl":"10.1038/s42005-024-01856-7","url":null,"abstract":"The application of terahertz technology in space is frontier for the development of 6G technologies. Terahertz transceiver devices based on gallium arsenide Schottky barrier diodes (GaAs SBDs) have the characteristics of small size, light weight and low power consumption, making them suitable for application on spacecraft. However, there is currently a lack of experimental assessments on their space adaptability. Here, we study the radiation hardness of terahertz devices to determine their adaptability in complex space environments. We exposed GaAs SBDs and terahertz multipliers as typical terahertz devices to gamma rays and protons. The experimental results showed that the terahertz devices exhibited good tolerance to protons, but prolonged exposure to gamma rays could significantly increase the leakage current of the GaAs SBDs and alter its C-V characteristics, leading to the failure of the terahertz multiplier. Nevertheless, the terahertz devices maintained a good level of radiation hardness, making them highly suitable for use in Low Earth Orbit (LEO) satellites. The comparison between the results of proton and gamma ray tests indicated that the terahertz devices exhibited high inherent radiation hardness against displacement damage but were more sensitive to ionization damage, requiring higher shielding requirements. Terahertz technology holds tremendous potential for application in high-speed, high-capacity space communication missions, yet there currently exists a lack of research on the space adaptability of its key components. The authors have conducted radiation hardness testing of gallium arsenide terahertz devices through ground-based simulated irradiation experiments.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-12"},"PeriodicalIF":5.4,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01856-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142588300","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 : 2024-11-06DOI: 10.1038/s42005-024-01851-y
Ryusuke Hamazaki
Fluctuation dynamics of an experimentally measured observable offer a primary signal for nonequilibrium systems, along with dynamics of the mean. While universal speed limits for the mean have actively been studied recently, constraints for the speed of the fluctuation have been elusive. Here, we develop a theory concerning rigorous limits to the rate of fluctuation growth. We find a principle that the speed of an observable’s fluctuation is upper bounded by the fluctuation of an appropriate observable describing velocity, which also indicates a tradeoff relation between the changes for the mean and fluctuation. We demonstrate the advantages of our inequalities for processes with non-negligible dispersion of observables, quantum work extraction, and the entanglement growth in free fermionic systems. Our results open an avenue toward a quantitative theory of fluctuation dynamics in various non-equilibrium systems encompassing quantum many-body systems and nonlinear population dynamics. Fluctuation dynamics of an observable offers a primary signal for understanding non-equilibrium statistical mechanics. Here, the author derives a principle that the speed of an observable’s fluctuation is upper bounded by the fluctuation of an observable describing velocity, which is valid for various non-equilibrium systems from quantum many-body systems to nonlinear population dynamics.
{"title":"Speed limits to fluctuation dynamics","authors":"Ryusuke Hamazaki","doi":"10.1038/s42005-024-01851-y","DOIUrl":"10.1038/s42005-024-01851-y","url":null,"abstract":"Fluctuation dynamics of an experimentally measured observable offer a primary signal for nonequilibrium systems, along with dynamics of the mean. While universal speed limits for the mean have actively been studied recently, constraints for the speed of the fluctuation have been elusive. Here, we develop a theory concerning rigorous limits to the rate of fluctuation growth. We find a principle that the speed of an observable’s fluctuation is upper bounded by the fluctuation of an appropriate observable describing velocity, which also indicates a tradeoff relation between the changes for the mean and fluctuation. We demonstrate the advantages of our inequalities for processes with non-negligible dispersion of observables, quantum work extraction, and the entanglement growth in free fermionic systems. Our results open an avenue toward a quantitative theory of fluctuation dynamics in various non-equilibrium systems encompassing quantum many-body systems and nonlinear population dynamics. Fluctuation dynamics of an observable offers a primary signal for understanding non-equilibrium statistical mechanics. Here, the author derives a principle that the speed of an observable’s fluctuation is upper bounded by the fluctuation of an observable describing velocity, which is valid for various non-equilibrium systems from quantum many-body systems to nonlinear population dynamics.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-11"},"PeriodicalIF":5.4,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01851-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142588289","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}
Delay-bandwidth product (DBP) is a key metric in slow light waveguides, requiring a balance between a large group index and broad bandwidth—two parameters that often involve a trade-off. Here, we propose and demonstrate a slow light waveguide with large DBP using a pseudospin-polarized transverse electromagnetic mode. This waveguide features a folded edge configuration that supports a 200% relative bandwidth from quasistatic limit (zero frequency) and an arbitrarily large group index. Owing to the pseudospin-polarized design, the dense folding would not introduce backscattering and the associated group velocity dispersion (GVD). The resulting gapless linear dispersion and pulse transmission behavior in folded edge waveguide are observed in microwave experiments. Our scheme provides a way to overcome the trade-off between group index and working bandwidth in slow light waveguide, which has potential applications in broadband optical buffering, light-matter interaction enhancement, terahertz radiation source and time domain processing. Delay-bandwidth product (DBP), which require a large group index and a wide bandwidth, is an important indicator in slow light waveguides. This work relaxes the trade-off between group velocity and working bandwidth in 200% relative bandwidth, and realizes a pseudospin-polarized slow-light waveguide with large DBP and low group velocity dispersion.
{"title":"Pseudospin-polarized slow light waveguides with large delay-bandwidth product","authors":"Fu-Long Shi, Xiao-Dong Chen, Wen-Jie Chen, Jian-Wen Dong","doi":"10.1038/s42005-024-01853-w","DOIUrl":"10.1038/s42005-024-01853-w","url":null,"abstract":"Delay-bandwidth product (DBP) is a key metric in slow light waveguides, requiring a balance between a large group index and broad bandwidth—two parameters that often involve a trade-off. Here, we propose and demonstrate a slow light waveguide with large DBP using a pseudospin-polarized transverse electromagnetic mode. This waveguide features a folded edge configuration that supports a 200% relative bandwidth from quasistatic limit (zero frequency) and an arbitrarily large group index. Owing to the pseudospin-polarized design, the dense folding would not introduce backscattering and the associated group velocity dispersion (GVD). The resulting gapless linear dispersion and pulse transmission behavior in folded edge waveguide are observed in microwave experiments. Our scheme provides a way to overcome the trade-off between group index and working bandwidth in slow light waveguide, which has potential applications in broadband optical buffering, light-matter interaction enhancement, terahertz radiation source and time domain processing. Delay-bandwidth product (DBP), which require a large group index and a wide bandwidth, is an important indicator in slow light waveguides. This work relaxes the trade-off between group velocity and working bandwidth in 200% relative bandwidth, and realizes a pseudospin-polarized slow-light waveguide with large DBP and low group velocity dispersion.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-7"},"PeriodicalIF":5.4,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01853-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142566002","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 : 2024-11-02DOI: 10.1038/s42005-024-01847-8
Harindranath B. Ambalampitiya, J. M. Ngoko Djiokap
The discovery and measurements of symmetric normal Archimedean spirals from atomic ionization by a pair of time-delayed broadband oppositely circularly polarized pulses revealed their potential of discerning orbital symmetry in atoms. Transferring this tool to molecules substantially increases experimental and theoretical challenges. Here, we show how Einstein’s photoelectric effect bypasses the congestion of electronic intermediate states and can access the orbital symmetry in heteronuclear, multi-orbital aligned molecules. Thanks to the broad bandwidth, multi-orbital ionization leads to multiplexed molecular-frame photoelectron momentum distributions, hiding thus any molecular orbital information. Only when molecular orientation is used to manipulate the ionization channels that one can identify a robust doorway into the molecular quantum world in which the asymmetry inherent to the highest-occupied molecular orbital can be unambiguously revealed by the asymmetric molecular spirals from single-color pulses. Our results demonstrate the potential of polarization-tailored attopulse sequences for the retrieval of spectroscopic details on molecular orbital symmetries. For pulse bandwidth larger than the energy gap between molecular orbitals, distinguishing contributions of electrons photoionized from different orbitals is a major hurdle. Here, the authors mitigate this issue by rotating light with respect to the molecular axis and show that asymmetric spirals are a new source of information for molecular orbital symmetries.
{"title":"Orientation-dependent production of normal Archimedean and dynamical spirals for revealing orbital symmetries in diatomic multi-orbital molecules","authors":"Harindranath B. Ambalampitiya, J. M. Ngoko Djiokap","doi":"10.1038/s42005-024-01847-8","DOIUrl":"10.1038/s42005-024-01847-8","url":null,"abstract":"The discovery and measurements of symmetric normal Archimedean spirals from atomic ionization by a pair of time-delayed broadband oppositely circularly polarized pulses revealed their potential of discerning orbital symmetry in atoms. Transferring this tool to molecules substantially increases experimental and theoretical challenges. Here, we show how Einstein’s photoelectric effect bypasses the congestion of electronic intermediate states and can access the orbital symmetry in heteronuclear, multi-orbital aligned molecules. Thanks to the broad bandwidth, multi-orbital ionization leads to multiplexed molecular-frame photoelectron momentum distributions, hiding thus any molecular orbital information. Only when molecular orientation is used to manipulate the ionization channels that one can identify a robust doorway into the molecular quantum world in which the asymmetry inherent to the highest-occupied molecular orbital can be unambiguously revealed by the asymmetric molecular spirals from single-color pulses. Our results demonstrate the potential of polarization-tailored attopulse sequences for the retrieval of spectroscopic details on molecular orbital symmetries. For pulse bandwidth larger than the energy gap between molecular orbitals, distinguishing contributions of electrons photoionized from different orbitals is a major hurdle. Here, the authors mitigate this issue by rotating light with respect to the molecular axis and show that asymmetric spirals are a new source of information for molecular orbital symmetries.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-14"},"PeriodicalIF":5.4,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01847-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142566003","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/s42005-024-01839-8
Jean L. Rintoul, Esra Neufeld, Chris Butler, Robin O. Cleveland, Nir Grossman
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Quantum teleportation is the process of transferring quantum information using classical communication and pre-shared entanglement. This process can benefit from the use of catalysts, which are ancillary entangled states that can enhance teleportation without being consumed. While chemical catalysts undergoing deactivation invariably exhibit inferior performance compared to those unaffected by deactivation, quantum catalysts, termed embezzling catalysts, that are subject to deactivation, may outperform their non-deactivating counterparts. In this work, we present teleportation protocols with embezzling catalysts that can achieve arbitrarily high fidelity. This enables the teleported state to closely approximate the original message state with arbitrary precision, while maintaining arbitrarily small variations in the catalytic system through the use of finite-dimensional embezzling catalysts. We show that some embezzling catalysts are universal, meaning that they can improve the teleportation fidelity for any pre-shared entanglement. We also explore methods to reduce the dimension of catalysts without increasing catalyst consumption, an essential step towards realizing quantum catalysis in practice. Quantum teleportation offers superior performance in transmitting information over classical methods but is often hindered by environmental noise. To address this issue, the authors introduce a teleportation protocol with finite-dimensional embezzling catalysts to achieve arbitrarily high fidelity, with only negligible changes to the catalytic systems.
{"title":"Teleportation with embezzling catalysts","authors":"Junjing Xing, Yuqi Li, Dengke Qu, Lei Xiao, Zhaobing Fan, Haitao Ma, Peng Xue, Kishor Bharti, Dax Enshan Koh, Yunlong Xiao","doi":"10.1038/s42005-024-01828-x","DOIUrl":"10.1038/s42005-024-01828-x","url":null,"abstract":"Quantum teleportation is the process of transferring quantum information using classical communication and pre-shared entanglement. This process can benefit from the use of catalysts, which are ancillary entangled states that can enhance teleportation without being consumed. While chemical catalysts undergoing deactivation invariably exhibit inferior performance compared to those unaffected by deactivation, quantum catalysts, termed embezzling catalysts, that are subject to deactivation, may outperform their non-deactivating counterparts. In this work, we present teleportation protocols with embezzling catalysts that can achieve arbitrarily high fidelity. This enables the teleported state to closely approximate the original message state with arbitrary precision, while maintaining arbitrarily small variations in the catalytic system through the use of finite-dimensional embezzling catalysts. We show that some embezzling catalysts are universal, meaning that they can improve the teleportation fidelity for any pre-shared entanglement. We also explore methods to reduce the dimension of catalysts without increasing catalyst consumption, an essential step towards realizing quantum catalysis in practice. Quantum teleportation offers superior performance in transmitting information over classical methods but is often hindered by environmental noise. To address this issue, the authors introduce a teleportation protocol with finite-dimensional embezzling catalysts to achieve arbitrarily high fidelity, with only negligible changes to the catalytic systems.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-16"},"PeriodicalIF":5.4,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01828-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142555510","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}
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