Pub Date : 2024-10-10DOI: 10.1038/s42005-024-01821-4
Cristina Garcia-Iriepa, Luis Manuel Frutos, Marco Marazzi
The evaluation of the Z/E photoisomerization efficiency is an essential task to design photoactive molecular devices. Nevertheless, this photoreactivity can be correctly described only by applying extensive and expensive computational methods. In this study, a predictive tool to screen the photoinduced Z/E isomerization efficiency of molecular switches is presented, based on three key properties: the structure of the ground state minimum, the nature of the electronic transition populating the optically bright state, and the presence of crossings between the optically bright state and the one lower in energy. Our methodology allows evaluating these properties by few and affordable calculations, potentially enabling the screening of large sets of photoswitches. After presenting the formal aspects, the tool is applied to model systems of paradigmatic classes of photoswitches (retinal, green fluorescent protein, hemithioindigo, chiroptical, and stilbene compounds) including derivatives. A comparison with the available experimental data is performed to validate our approach. Cis-trans photoisomerization is a key process for many processes in biology and materials science, but only careful and time-consuming quantum chemistry methods can describe such reaction in detail. Here, a predictive tool is presented requiring few and affordable calculations, evaluating the efficiency of paradigmatic and modified photoswitches.
{"title":"A predictive screening tool to evaluate the efficiency of Z/E photoisomerizable molecular switches","authors":"Cristina Garcia-Iriepa, Luis Manuel Frutos, Marco Marazzi","doi":"10.1038/s42005-024-01821-4","DOIUrl":"10.1038/s42005-024-01821-4","url":null,"abstract":"The evaluation of the Z/E photoisomerization efficiency is an essential task to design photoactive molecular devices. Nevertheless, this photoreactivity can be correctly described only by applying extensive and expensive computational methods. In this study, a predictive tool to screen the photoinduced Z/E isomerization efficiency of molecular switches is presented, based on three key properties: the structure of the ground state minimum, the nature of the electronic transition populating the optically bright state, and the presence of crossings between the optically bright state and the one lower in energy. Our methodology allows evaluating these properties by few and affordable calculations, potentially enabling the screening of large sets of photoswitches. After presenting the formal aspects, the tool is applied to model systems of paradigmatic classes of photoswitches (retinal, green fluorescent protein, hemithioindigo, chiroptical, and stilbene compounds) including derivatives. A comparison with the available experimental data is performed to validate our approach. Cis-trans photoisomerization is a key process for many processes in biology and materials science, but only careful and time-consuming quantum chemistry methods can describe such reaction in detail. Here, a predictive tool is presented requiring few and affordable calculations, evaluating the efficiency of paradigmatic and modified photoswitches.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-12"},"PeriodicalIF":5.4,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01821-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142443616","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}
Quantum error mitigation (QEM) is vital for improving quantum algorithms’ accuracy on noisy near-term devices. A typical QEM method, called Virtual Distillation (VD), can suffer from imperfect implementation, potentially leading to worse outcomes than without mitigation. To address this, we introduce Circuit-Noise-Resilient Virtual Distillation (CNR-VD), which includes a calibration process using simple input states to enhance VD’s performance despite circuit noise, aiming to recover the results of an ideally conducted VD circuit. Simulations show that CNR-VD significantly mitigates noise-induced errors in VD circuits, boosting accuracy by up to tenfold over standard VD. It provides positive error mitigation even under high noise, where standard VD fails. Furthermore, our estimator’s versatility extends its utility beyond VD, enhancing outcomes in general Hadamard-Test circuits. The proposed CNR-VD significantly enhances the noise-resilience of VD, and thus is anticipated to elevate the performance of quantum algorithm implementations on near-term quantum devices. This study focuses on reducing noise in the circuit used in the quantum error mitigation method called Virtual Distillation (VD). The authors introduce an approach which significantly enhances the noise tolerance of VD and improves the accuracy by an order of magnitude compared to the standard VD.
{"title":"Circuit-noise-resilient virtual distillation","authors":"Xiao-Yue Xu, Chen Ding, Shuo Zhang, Wan-Su Bao, He-Liang Huang","doi":"10.1038/s42005-024-01815-2","DOIUrl":"10.1038/s42005-024-01815-2","url":null,"abstract":"Quantum error mitigation (QEM) is vital for improving quantum algorithms’ accuracy on noisy near-term devices. A typical QEM method, called Virtual Distillation (VD), can suffer from imperfect implementation, potentially leading to worse outcomes than without mitigation. To address this, we introduce Circuit-Noise-Resilient Virtual Distillation (CNR-VD), which includes a calibration process using simple input states to enhance VD’s performance despite circuit noise, aiming to recover the results of an ideally conducted VD circuit. Simulations show that CNR-VD significantly mitigates noise-induced errors in VD circuits, boosting accuracy by up to tenfold over standard VD. It provides positive error mitigation even under high noise, where standard VD fails. Furthermore, our estimator’s versatility extends its utility beyond VD, enhancing outcomes in general Hadamard-Test circuits. The proposed CNR-VD significantly enhances the noise-resilience of VD, and thus is anticipated to elevate the performance of quantum algorithm implementations on near-term quantum devices. This study focuses on reducing noise in the circuit used in the quantum error mitigation method called Virtual Distillation (VD). The authors introduce an approach which significantly enhances the noise tolerance of VD and improves the accuracy by an order of magnitude compared to the standard VD.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-7"},"PeriodicalIF":5.4,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01815-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142443630","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 : 2024-10-08DOI: 10.1038/s42005-024-01814-3
Ying Sun, Li Zhu
Recent advances in the search for room-temperature superconductors have focused on high-temperature superconductivity in compressed hydrides, though sustaining this at ambient pressure remains challenging. Concurrently, sp3-bonded frameworks comprising lightweight elements offer another avenue for ambient-pressure superconductors. However, their critical temperatures (Tc) still fall short of those in hydrides. Here we propose a design strategy for achieving high-temperature superconductivity at ambient pressure by integrating hydride units into B–C clathrate structures. This approach exploits the beneficial properties of hydrogen, the lightest element, to enhance superconductivity beyond that of the parent compounds. Our computational predictions indicate that doping SrB3C3 with ammonium (NH4) produces SrNH4B6C6, with an estimated Tc of 85 K at ambient pressure—over twice that of its precursor (31 K). Further substitutions yield a family of MNH4B6C6 superconductors, with PbNH4B6C6 predicted to reach a Tc of 115 K. These findings offer a promising route to high-Tc superconductors at ambient pressure. The quest for room-temperature superconductivity has been a long-standing aspiration and a central focus of research in the field of condensed matter physics. Here, the authors propose integrating hydride units into Boron-Carbon clathrate structures to achieve high-temperature superconductivity at ambient pressure.
{"title":"Hydride units filled boron–carbon clathrate: a pathway for high-temperature superconductivity at ambient pressure","authors":"Ying Sun, Li Zhu","doi":"10.1038/s42005-024-01814-3","DOIUrl":"10.1038/s42005-024-01814-3","url":null,"abstract":"Recent advances in the search for room-temperature superconductors have focused on high-temperature superconductivity in compressed hydrides, though sustaining this at ambient pressure remains challenging. Concurrently, sp3-bonded frameworks comprising lightweight elements offer another avenue for ambient-pressure superconductors. However, their critical temperatures (Tc) still fall short of those in hydrides. Here we propose a design strategy for achieving high-temperature superconductivity at ambient pressure by integrating hydride units into B–C clathrate structures. This approach exploits the beneficial properties of hydrogen, the lightest element, to enhance superconductivity beyond that of the parent compounds. Our computational predictions indicate that doping SrB3C3 with ammonium (NH4) produces SrNH4B6C6, with an estimated Tc of 85 K at ambient pressure—over twice that of its precursor (31 K). Further substitutions yield a family of MNH4B6C6 superconductors, with PbNH4B6C6 predicted to reach a Tc of 115 K. These findings offer a promising route to high-Tc superconductors at ambient pressure. The quest for room-temperature superconductivity has been a long-standing aspiration and a central focus of research in the field of condensed matter physics. Here, the authors propose integrating hydride units into Boron-Carbon clathrate structures to achieve high-temperature superconductivity at ambient pressure.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-8"},"PeriodicalIF":5.4,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01814-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142443636","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 : 2024-10-07DOI: 10.1038/s42005-024-01806-3
Heorhii Bohuslavskyi, Alberto Ronzani, Joel Hätinen, Arto Rantala, Andrey Shchepetov, Panu Koppinen, Janne S. Lehtinen, Mika Prunnila
Owing to the maturity of complementary metal oxide semiconductor (CMOS) microelectronics, qubits realized with spins in silicon quantum dots (QDs) are considered among the most promising technologies for building scalable quantum computers. For this goal, ultra-low-power on-chip cryogenic CMOS (cryo-CMOS) electronics for control, read-out, and interfacing of the qubits is an important milestone. We report on-chip interfacing of tunable electron and hole QDs by a 64-channel cryo-CMOS multiplexer with less-than-detectable static power dissipation. We analyze charge noise and measure state-of-the-art addition energies and gate lever arm parameters in the QDs. We correlate low noise in QDs and sharp turn-on characteristics in cryogenic transistors, both fabricated with the same gate stack. Finally, we demonstrate that our hybrid quantum-CMOS technology provides a route to scalable interfacing of a large number of QD devices, enabling, for example, variability analysis and QD qubit geometry optimization, which are prerequisites for building large-scale silicon-based quantum computers. The integration of quantum dot spin qubits and classical cryogenic microelectronics is important for scaling up silicon-based quantum computers. The authors show that their silicon technology tailored for low-power electronics and low-noise quantum dots enables the integration of classical multiplexers and quantum dot spin qubit devices on the same chip.
{"title":"Scalable on-chip multiplexing of silicon single and double quantum dots","authors":"Heorhii Bohuslavskyi, Alberto Ronzani, Joel Hätinen, Arto Rantala, Andrey Shchepetov, Panu Koppinen, Janne S. Lehtinen, Mika Prunnila","doi":"10.1038/s42005-024-01806-3","DOIUrl":"10.1038/s42005-024-01806-3","url":null,"abstract":"Owing to the maturity of complementary metal oxide semiconductor (CMOS) microelectronics, qubits realized with spins in silicon quantum dots (QDs) are considered among the most promising technologies for building scalable quantum computers. For this goal, ultra-low-power on-chip cryogenic CMOS (cryo-CMOS) electronics for control, read-out, and interfacing of the qubits is an important milestone. We report on-chip interfacing of tunable electron and hole QDs by a 64-channel cryo-CMOS multiplexer with less-than-detectable static power dissipation. We analyze charge noise and measure state-of-the-art addition energies and gate lever arm parameters in the QDs. We correlate low noise in QDs and sharp turn-on characteristics in cryogenic transistors, both fabricated with the same gate stack. Finally, we demonstrate that our hybrid quantum-CMOS technology provides a route to scalable interfacing of a large number of QD devices, enabling, for example, variability analysis and QD qubit geometry optimization, which are prerequisites for building large-scale silicon-based quantum computers. The integration of quantum dot spin qubits and classical cryogenic microelectronics is important for scaling up silicon-based quantum computers. The authors show that their silicon technology tailored for low-power electronics and low-noise quantum dots enables the integration of classical multiplexers and quantum dot spin qubit devices on the same chip.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-10"},"PeriodicalIF":5.4,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01806-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142443609","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 : 2024-10-06DOI: 10.1038/s42005-024-01813-4
Yuchen Guo, Shuo Yang
Understanding quantum systems is of significant importance for assessing the performance of quantum hardware and software, as well as exploring quantum control and quantum sensing. An efficient representation of quantum states enables realizing quantum state tomography with minimal measurements. In this study, we propose an alternative approach to state tomography that uses tensor network representations of mixed states through locally purified density operators and employs a classical data postprocessing algorithm requiring only local measurements. Through numerical simulations of one-dimensional pure and mixed states and two-dimensional pure states up to size 8 × 8, we demonstrate the efficiency, accuracy, and robustness of our proposed methods. Experiments on the IBM and Quafu Quantum platforms complement these numerical simulations. Our study opens avenues in quantum state tomography for two-dimensional systems using tensor network formalism. Quantum state tomography is a fundamental tool for assessing the performance of quantum hardware and plays a crucial role in advancing quantum information processing. The authors present a method based on tensor network representations and local measurements, demonstrating accuracy and efficiency in characterizing noisy quantum states.
了解量子系统对于评估量子硬件和软件的性能以及探索量子控制和量子传感具有重要意义。量子态的高效表示能够以最少的测量实现量子态层析。在本研究中，我们提出了另一种状态层析方法，即通过局部纯化的密度算子使用张量网络表示混合状态，并采用只需局部测量的经典数据后处理算法。通过对一维纯态和混合态以及最大尺寸为 8 × 8 的二维纯态进行数值模拟，我们证明了所提方法的效率、准确性和鲁棒性。在 IBM 和 Quafu Quantum 平台上进行的实验是对这些数值模拟的补充。我们的研究开辟了利用张量网络形式主义进行二维系统量子态层析的途径。量子态层析是评估量子硬件性能的基本工具，在推动量子信息处理方面发挥着至关重要的作用。作者提出了一种基于张量网络表征和局部测量的方法，展示了表征噪声量子态的准确性和效率。
{"title":"Quantum state tomography with locally purified density operators and local measurements","authors":"Yuchen Guo, Shuo Yang","doi":"10.1038/s42005-024-01813-4","DOIUrl":"10.1038/s42005-024-01813-4","url":null,"abstract":"Understanding quantum systems is of significant importance for assessing the performance of quantum hardware and software, as well as exploring quantum control and quantum sensing. An efficient representation of quantum states enables realizing quantum state tomography with minimal measurements. In this study, we propose an alternative approach to state tomography that uses tensor network representations of mixed states through locally purified density operators and employs a classical data postprocessing algorithm requiring only local measurements. Through numerical simulations of one-dimensional pure and mixed states and two-dimensional pure states up to size 8 × 8, we demonstrate the efficiency, accuracy, and robustness of our proposed methods. Experiments on the IBM and Quafu Quantum platforms complement these numerical simulations. Our study opens avenues in quantum state tomography for two-dimensional systems using tensor network formalism. Quantum state tomography is a fundamental tool for assessing the performance of quantum hardware and plays a crucial role in advancing quantum information processing. The authors present a method based on tensor network representations and local measurements, demonstrating accuracy and efficiency in characterizing noisy quantum states.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-11"},"PeriodicalIF":5.4,"publicationDate":"2024-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01813-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142447861","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 : 2024-10-06DOI: 10.1038/s42005-024-01812-5
Paula García-Molina, Ana Martin, Mikel Garcia de Andoin, Mikel Sanz
Noisy Intermediate-Scale Quantum (NISQ) devices lack error correction, limiting scalability for quantum algorithms. In this context, digital-analog quantum computing (DAQC) offers a more resilient alternative quantum computing paradigm that outperforms digital quantum computation by combining the flexibility of single-qubit gates with the robustness of analog simulations. This work explores the impact of noise on both digital and DAQC paradigms and demonstrates DAQC’s effectiveness in error mitigation. We compare the quantum Fourier transform and quantum phase estimation algorithms under a wide range of single and two-qubit noise sources in superconducting processors. DAQC consistently surpasses digital approaches in fidelity, particularly as processor size increases. Moreover, zero-noise extrapolation further enhances DAQC by mitigating decoherence and intrinsic errors, achieving fidelities above 0.95 for 8 qubits, and reducing computation errors to the order of 10−3. These results establish DAQC as a viable alternative for quantum computing in the NISQ era. The authors explore the digital-analog quantum computing paradigm, which combines fast single-qubit gates with the natural dynamics of quantum devices. They find the digital-analog paradigm more robust against certain experimental imperfections than the standard fully-digital one and successfully apply error mitigation techniques to this approach.
{"title":"Mitigating noise in digital and digital–analog quantum computation","authors":"Paula García-Molina, Ana Martin, Mikel Garcia de Andoin, Mikel Sanz","doi":"10.1038/s42005-024-01812-5","DOIUrl":"10.1038/s42005-024-01812-5","url":null,"abstract":"Noisy Intermediate-Scale Quantum (NISQ) devices lack error correction, limiting scalability for quantum algorithms. In this context, digital-analog quantum computing (DAQC) offers a more resilient alternative quantum computing paradigm that outperforms digital quantum computation by combining the flexibility of single-qubit gates with the robustness of analog simulations. This work explores the impact of noise on both digital and DAQC paradigms and demonstrates DAQC’s effectiveness in error mitigation. We compare the quantum Fourier transform and quantum phase estimation algorithms under a wide range of single and two-qubit noise sources in superconducting processors. DAQC consistently surpasses digital approaches in fidelity, particularly as processor size increases. Moreover, zero-noise extrapolation further enhances DAQC by mitigating decoherence and intrinsic errors, achieving fidelities above 0.95 for 8 qubits, and reducing computation errors to the order of 10−3. These results establish DAQC as a viable alternative for quantum computing in the NISQ era. The authors explore the digital-analog quantum computing paradigm, which combines fast single-qubit gates with the natural dynamics of quantum devices. They find the digital-analog paradigm more robust against certain experimental imperfections than the standard fully-digital one and successfully apply error mitigation techniques to this approach.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-10"},"PeriodicalIF":5.4,"publicationDate":"2024-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01812-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142443637","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 : 2024-10-05DOI: 10.1038/s42005-024-01808-1
Yisheng Gao
Metasurfaces are established tools for manipulating light and enhancing light-matter interactions. However, the loss of conventional meta-atoms usually limits the performance potential of metasurfaces. In this study, we propose a class of metasurfaces based on discretized meta-atoms able to mitigate the radiative and intrinsic losses. By discretizing meta-atoms, we reduce the loss of metal metasurfaces to levels comparable to dielectric metasurfaces in the short-wavelength infrared region at the surface lattice resonance mode. Furthermore, we propose a coupling model to explain the observed reduction in loss in full agreement with the results obtained from finite-element method. We also reproduce this phenomenon using dielectric metasurface at electric and magnetic resonances in the visible region. Our finding offers valuable insights for the design and application of metasurfaces, while also providing theoretical implications for other resonance fields beyond metasurfaces. Metasurfaces are established tools for manipulating light and enhancing light-matter interactions, but the loss of conventional meta-atoms usually limits the performance potential of metasurfaces. Here, the authors propose a class of metasurfaces based on discretized meta-atoms able to mitigate the radiative and intrinsic losses, as interpreted by their built coupling model.
{"title":"Low-loss metasurfaces based on discretized meta-atoms","authors":"Yisheng Gao","doi":"10.1038/s42005-024-01808-1","DOIUrl":"10.1038/s42005-024-01808-1","url":null,"abstract":"Metasurfaces are established tools for manipulating light and enhancing light-matter interactions. However, the loss of conventional meta-atoms usually limits the performance potential of metasurfaces. In this study, we propose a class of metasurfaces based on discretized meta-atoms able to mitigate the radiative and intrinsic losses. By discretizing meta-atoms, we reduce the loss of metal metasurfaces to levels comparable to dielectric metasurfaces in the short-wavelength infrared region at the surface lattice resonance mode. Furthermore, we propose a coupling model to explain the observed reduction in loss in full agreement with the results obtained from finite-element method. We also reproduce this phenomenon using dielectric metasurface at electric and magnetic resonances in the visible region. Our finding offers valuable insights for the design and application of metasurfaces, while also providing theoretical implications for other resonance fields beyond metasurfaces. Metasurfaces are established tools for manipulating light and enhancing light-matter interactions, but the loss of conventional meta-atoms usually limits the performance potential of metasurfaces. Here, the authors propose a class of metasurfaces based on discretized meta-atoms able to mitigate the radiative and intrinsic losses, as interpreted by their built coupling model.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-7"},"PeriodicalIF":5.4,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01808-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142447909","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 : 2024-10-04DOI: 10.1038/s42005-024-01809-0
Saeed S. Jahromi, Max Hörmann, Patrick Adelhardt, Sebastian Fey, Hooman Karamnejad, Román Orús, Kai Phillip Schmidt
We use tensor-network methods and high-order linked-cluster expansions to explore the quantum phase diagram of the antiferromagnetic Kitaev honeycomb model in a magnetic field for general spin S values. Tensor network calculations for the pure Kitaev model confirm the absence of fluxes and spin-spin correlations beyond nearest neighbors, while revealing discrete orientational symmetry breaking for S ∈ 1, 3/2, 2, consistent with the semiclassical limit. An intermediate region between Kitaev phases and the high-field polarized phase is identified for all considered spin values, showing a sequence of potential phases characterized by distinct local magnetization patterns while the total magnetization increases smoothly as a function of the field. Linked-cluster expansions for the high-field zero-momentum gap and spectral weight indicate a quantum critical breakdown of the polarized phase, suggesting exotic physics at intermediate Kitaev couplings. The antiferromagnetic spin 1/2 Kitaev model is known to have an intermediate phase under a magnetic field before transitioning to a fully polarized state. However, the nature of this phase for higher spins remained unclear. This paper explores the quantum phase diagram of the antiferromagnetic Kitaev honeycomb model in a magnetic field using tensor-network methods and high-order linked cluster expansions, uncovering an intermediate phase with distinct local magnetization patterns across different spin values.
我们使用张量网络方法和高阶联簇展开来探索反铁磁基塔耶夫蜂巢模型在磁场中一般自旋 S 值的量子相图。对纯基塔耶夫模型的张量网络计算证实，在近邻之外不存在通量和自旋-自旋相关性，同时揭示了S ∈ 1, 3/2, 2的离散方向对称性破缺，这与半经典极限一致。在所有考虑的自旋值中，都确定了介于基塔耶夫相和高场极化相之间的中间区域，显示了一连串以独特的局部磁化模式为特征的势相，而总磁化则随着场的函数平滑增加。对高场零动量间隙和光谱权重的关联簇展开表明，极化相存在量子临界崩溃，暗示了中间基塔耶夫耦合的奇异物理学。众所周知，反铁磁自旋 1/2 基塔耶夫模型在过渡到完全极化态之前，在磁场作用下有一个中间阶段。然而，对于更高的自旋，这一阶段的性质仍不清楚。本文利用张量网络方法和高阶链接簇展开，探索了反铁磁性基塔耶夫蜂巢模型在磁场中的量子相图，发现了在不同自旋值下具有不同局部磁化模式的中间阶段。
{"title":"Kitaev honeycomb antiferromagnet in a field: quantum phase diagram for general spin","authors":"Saeed S. Jahromi, Max Hörmann, Patrick Adelhardt, Sebastian Fey, Hooman Karamnejad, Román Orús, Kai Phillip Schmidt","doi":"10.1038/s42005-024-01809-0","DOIUrl":"10.1038/s42005-024-01809-0","url":null,"abstract":"We use tensor-network methods and high-order linked-cluster expansions to explore the quantum phase diagram of the antiferromagnetic Kitaev honeycomb model in a magnetic field for general spin S values. Tensor network calculations for the pure Kitaev model confirm the absence of fluxes and spin-spin correlations beyond nearest neighbors, while revealing discrete orientational symmetry breaking for S ∈ 1, 3/2, 2, consistent with the semiclassical limit. An intermediate region between Kitaev phases and the high-field polarized phase is identified for all considered spin values, showing a sequence of potential phases characterized by distinct local magnetization patterns while the total magnetization increases smoothly as a function of the field. Linked-cluster expansions for the high-field zero-momentum gap and spectral weight indicate a quantum critical breakdown of the polarized phase, suggesting exotic physics at intermediate Kitaev couplings. The antiferromagnetic spin 1/2 Kitaev model is known to have an intermediate phase under a magnetic field before transitioning to a fully polarized state. However, the nature of this phase for higher spins remained unclear. This paper explores the quantum phase diagram of the antiferromagnetic Kitaev honeycomb model in a magnetic field using tensor-network methods and high-order linked cluster expansions, uncovering an intermediate phase with distinct local magnetization patterns across different spin values.","PeriodicalId":10540,"journal":{"name":"Communications Physics","volume":" ","pages":"1-8"},"PeriodicalIF":5.4,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s42005-024-01809-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142377230","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 : 2024-10-04DOI: 10.1038/s42005-024-01800-9
Hoai Anh Ho, Jian Huang, L. N. Pfeiffer, K. W. West
Topology is essential for achieving unchanged (or protected) quantum properties in the presence of perturbations. A challenge facing the application is the variable protection levels displayed in real systems associated with the reconstructive behaviors of the dissipationless modes. Despite various insights on potential causes of backscattering, the edge-state-based approach is incomplete because the bulk states also contribute indispensably. This study investigates sample-scale reconstruction where dissipationless modes are global objects instead of being restricted to the sample edge. An integer quantum Hall effect hosted in a Corbino geometry is adopted and brought to the verge of a breakdown. Two independent and simultaneous detections are performed to capture transport responses in both longitudinal and transverse directions. The real-time correspondence between orthogonal results confirms two facts. 1. Dissipationless modes undergo frequent reconstruction in response to electrochemical potential changes, causing dissipationless current paths to expand transversely into the bulk while preserving chirality. A breakdown only occurs when a backscattering emerges between reconstructed dissipationless current paths bridging opposite edge contacts. 2. Topological protection is subject to an interplay of disorder, electron-electron interaction, and topology. The proposed reconstruction mechanism qualitatively explains the robustness variations, beneficial for protection optimization. Understanding the mechanisms influencing the robustness of topologically protected states is of fundamental relevance. This experimental work demonstrates, through the observation of real-time longitudinal and transverse responses, the importance of transverse reconstruction of protected modes which is influenced by electron-electron interaction in addition to disorder.
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Pub Date : 2024-10-03DOI: 10.1038/s42005-024-01766-8
Lina Z. Hadid, Dominique Delcourt, Yuki Harada, Mathias Rojo, Sae Aizawa, Yoshifumi Saito, Nicolas André, Austin N. Glass, Jim M. Raines, Shoichiro Yokota, Markus Fränz, Bruno Katra, Christophe Verdeil, Björn Fiethe, Francois Leblanc, Ronan Modolo, Dominique Fontaine, Norbert Krupp, Harald Krüger, Frédéric Leblanc, Henning Fischer, Jean-Jacques Berthelier, Jean-André Sauvaud, Go Murakami, Shoya Matsuda
Understanding Mercury’s magnetosphere is crucial for advancing our comprehension of how the solar wind interacts with the planetary magnetospheres. Despite previous missions, several gaps remain in our knowledge of Mercury’s plasma environment. Here, we present findings from BepiColombo’s third flyby, offering a synoptic view of the large scale structure and composition of Mercury’s magnetosphere. The Mass Spectrum Analyzer (MSA), Mass Ion Analyzer (MIA), and Mass Electron Analyzer (MEA) on the magnetospheric orbiter reveal insights, including the identification of trapped energetic hydrogen (H+) with energies around 20 keV e−1 evidencing a ring current, and a cold ion plasma with energies below 50 eV e−1. Additionally, we observe a Low-Latitude Boundary Layer (LLBL), which is a region of turbulent plasma at the edge of the magnetosphere, characterized by bursty ion enhancements, indicating an ongoing injection process in the duskside magnetosphere flank. These observations during cruise phase provide a tantalizing glimpse of future discoveries expected from the Mercury Plasma Particle Experiment (MPPE) instruments after orbit insertion, promising broader impacts on our understanding of planetary magnetospheres. Due to its proximity to the Sun, the space plasma environment of Mercury is tightly coupled with the interior and the surface of the planet, and their interaction facilitate the escape of planetary material and energy exchange. The authors present data from the third flyby of the BepiColombo spacecraft revealing new evidence of trapped energetic hydrogen (H+) with energies of around 20 keV/e and highlight the presence of cold ion population below 50 eV/e in Mercury’s magnetosphere.
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