Pub Date : 2024-09-10DOI: 10.1103/physrevapplied.22.034023
Thomas Larsen, Jesper de C. Christiansen, John R. Royer, Fraser H.J. Laidlaw, Wilson C.K. Poon, Tom Larsen, Søren J. Andreasen
A unique bistable transition has been identified in granular-colloidal gel composites, resulting from shear-induced phase separation of the gel phase into dense blobs. In energy applications, it is critical to understand how this transition influences electrical performance. Mixing conductive colloids with conductive inclusions, we find that the conductivity and elasticity move in concert, both decreasing in the collapsed phase-separated state. Surprisingly, with insulating inclusions, these properties can become decoupled, with the conductivity instead increasing despite the collapse of the gel structure.
{"title":"Decoupling elasticity and electrical conductivity of carbon-black gels filled with insulating non-Brownian grains","authors":"Thomas Larsen, Jesper de C. Christiansen, John R. Royer, Fraser H.J. Laidlaw, Wilson C.K. Poon, Tom Larsen, Søren J. Andreasen","doi":"10.1103/physrevapplied.22.034023","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.034023","url":null,"abstract":"A unique bistable transition has been identified in granular-colloidal gel composites, resulting from shear-induced phase separation of the gel phase into dense blobs. In energy applications, it is critical to understand how this transition influences electrical performance. Mixing conductive colloids with conductive inclusions, we find that the conductivity and elasticity move in concert, both decreasing in the collapsed phase-separated state. Surprisingly, with insulating inclusions, these properties can become decoupled, with the conductivity instead increasing despite the collapse of the gel structure.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"41 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-10DOI: 10.1103/physrevapplied.22.034020
Sheng-Chen Liu, Lin Cheng, Liang-You Peng, Qihuang Gong
In the presence of physical noise of all platforms for quantum computation, quantum error correction (QEC) becomes a critical way to realize quantum algorithms with large quantum volumes. In order to understand the influence of quantum noise on QEC codes and further improve the performance of logical circuits, the noises should be accurately analyzed with proper models. Here we focus on the trapped-ion system. Fundamentally, we start from the laser pulses of the quantum gates in the circuits and extract the noise components from the complete evolution of the quantum states, beyond the standard depolarizing model and other simplified models. Our simulations indicate that the logical performance under real noises is significantly better than that predicted by previous models. Meanwhile, the advantage of QEC is shown in the levels of one, two, and more logical qubits. Moreover, we can increase the logical fidelity by the method of ion mapping, which is based on knowledge of the specific noise distribution of different ions. Some powerful evidence from the numerical results demonstrates the possibility to access fault-tolerant quantum computation with the trapped-ion system.
{"title":"Logical quantum circuits protected by the Steane code for specific noises in trapped ions","authors":"Sheng-Chen Liu, Lin Cheng, Liang-You Peng, Qihuang Gong","doi":"10.1103/physrevapplied.22.034020","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.034020","url":null,"abstract":"In the presence of physical noise of all platforms for quantum computation, quantum error correction (QEC) becomes a critical way to realize quantum algorithms with large quantum volumes. In order to understand the influence of quantum noise on QEC codes and further improve the performance of logical circuits, the noises should be accurately analyzed with proper models. Here we focus on the trapped-ion system. Fundamentally, we start from the laser pulses of the quantum gates in the circuits and extract the noise components from the complete evolution of the quantum states, beyond the standard depolarizing model and other simplified models. Our simulations indicate that the logical performance under real noises is significantly better than that predicted by previous models. Meanwhile, the advantage of QEC is shown in the levels of one, two, and more logical qubits. Moreover, we can increase the logical fidelity by the method of ion mapping, which is based on knowledge of the specific noise distribution of different ions. Some powerful evidence from the numerical results demonstrates the possibility to access fault-tolerant quantum computation with the trapped-ion system.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"23 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-09DOI: 10.1103/physrevapplied.22.034017
Jiacheng Liu, Yuzan Xiong, Jingming Liang, Xuezhao Wu, Chen Liu, Shun Kong Cheung, Zheyu Ren, Ruizi Liu, Andrew Christy, Zehan Chen, Yifan Liu, Ferris Prima Nugraha, Xi-Xiang Zhang, Dennis Chi Wah Leung, Wei Zhang, Qiming Shao
Magnetic insulators, such as yttrium iron garnets (YIGs), are important for spin-wave or magnonic devices as their low damping enables low-power dissipation. Magnetic insulator heterostructures can offer larger design space for realizing exotic magnonic quantum states, provided that individual layers have low damping and their exchange coupling is strong and engineerable. Here, we show that, in a high-quality all-insulator thulium iron garnet (TmIG)/YIG bilayer system, TmIG exhibits an ultralow dissipation rate thanks to its low-damping, low-saturation magnetization and strong orbital momentum. The low dissipation rates in both YIG and TmIG, along with their significant coupling strength due to interfacial exchange coupling, enable strong and coherent magnon-magnon coupling. The coupling strength can be tuned by varying the magnetic insulator layer thickness and magnon modes, which is consistent with analytical calculations and micromagnetic simulations. Our results demonstrate TmIG/YIG as a novel platform for investigating hybrid magnonic phenomena and open opportunities for magnon devices comprising all-insulator heterostructures.
{"title":"Strong magnon-magnon coupling and low dissipation rate in an all-magnetic-insulator heterostructure","authors":"Jiacheng Liu, Yuzan Xiong, Jingming Liang, Xuezhao Wu, Chen Liu, Shun Kong Cheung, Zheyu Ren, Ruizi Liu, Andrew Christy, Zehan Chen, Yifan Liu, Ferris Prima Nugraha, Xi-Xiang Zhang, Dennis Chi Wah Leung, Wei Zhang, Qiming Shao","doi":"10.1103/physrevapplied.22.034017","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.034017","url":null,"abstract":"Magnetic insulators, such as yttrium iron garnets (YIGs), are important for spin-wave or magnonic devices as their low damping enables low-power dissipation. Magnetic insulator heterostructures can offer larger design space for realizing exotic magnonic quantum states, provided that individual layers have low damping and their exchange coupling is strong and engineerable. Here, we show that, in a high-quality all-insulator thulium iron garnet (TmIG)/YIG bilayer system, TmIG exhibits an ultralow dissipation rate thanks to its low-damping, low-saturation magnetization and strong orbital momentum. The low dissipation rates in both YIG and TmIG, along with their significant coupling strength due to interfacial exchange coupling, enable strong and coherent magnon-magnon coupling. The coupling strength can be tuned by varying the magnetic insulator layer thickness and magnon modes, which is consistent with analytical calculations and micromagnetic simulations. Our results demonstrate TmIG/YIG as a novel platform for investigating hybrid magnonic phenomena and open opportunities for magnon devices comprising all-insulator heterostructures.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"4 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-09DOI: 10.1103/physrevapplied.22.034019
Anna M. Krol, Zaid Al-Ars
This paper proposes an optimized quantum block- decomposition method that results in more optimal quantum circuits than the quantum Shannon decomposition, which was presented in 2005 by M. Möttönen, and J. J. Vartiainen [in Trends in quantum computing research, edited by S. Shannon (Nova Science Publishers, 2006) Chap. 7, p. 149, arXiv:quant-ph/0504100]. The decomposition is applied recursively to generic quantum gates, and can take advantage of existing and future small-circuit optimizations. Because our method uses only single-qubit gates and uniformly controlled rotation-Z gates, it can easily be adapted to use other types of multi-qubit gates. With the proposed decomposition, a general three-qubit gate can be decomposed using 19 cnot gates (rather than 20). For general -qubit gates, the proposed decomposition generates circuits that have cnot gates, which is less than the best-known exact decomposition algorithm by cnot gates.
本文提出了一种优化的量子块-ZXZ分解方法，它比 M. Möttönen 和 J. J. Vartiainen 于 2005 年提出的量子香农分解方法[见 S. Shannon 编辑的《量子计算研究趋势》（新星科学出版社，2006 年）第 7 章第 149 页，arXiv:quant-ph/0504100]能产生更优化的量子电路。该分解方法可递归应用于通用量子门，并能利用现有和未来的小电路优化。由于我们的方法只使用单量子比特门和均匀控制的旋转-Z 门，因此很容易调整为使用其他类型的多量子比特门。使用我们提出的分解方法，一般的三量子位门可以用 19 个 cnot 门（而不是 20 个）来分解。对于一般的 n-qubit 门，所提出的分解方法生成的电路有 22484n-322n+53 个 cnot 门，比最著名的精确分解算法少 (4n-2-1)/3 个 cnot 门。
{"title":"Beyond quantum Shannon decomposition: Circuit construction for n-qubit gates based on block-ZXZ decomposition","authors":"Anna M. Krol, Zaid Al-Ars","doi":"10.1103/physrevapplied.22.034019","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.034019","url":null,"abstract":"This paper proposes an optimized quantum block-<math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Z</mi><mi>X</mi><mi>Z</mi></math> decomposition method that results in more optimal quantum circuits than the quantum Shannon decomposition, which was presented in 2005 by M. Möttönen, and J. J. Vartiainen [in <i>Trends in quantum computing research</i>, edited by S. Shannon (Nova Science Publishers, 2006) Chap. 7, p. 149, arXiv:quant-ph/0504100]. The decomposition is applied recursively to generic quantum gates, and can take advantage of existing and future small-circuit optimizations. Because our method uses only single-qubit gates and uniformly controlled rotation-Z gates, it can easily be adapted to use other types of multi-qubit gates. With the proposed decomposition, a general three-qubit gate can be decomposed using 19 <span>cnot</span> gates (rather than 20). For general <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>n</mi></math>-qubit gates, the proposed decomposition generates circuits that have <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mstyle displaystyle=\"false\" scriptlevel=\"0\"><mfrac><mn>22</mn><mn>48</mn></mfrac></mstyle><msup><mn>4</mn><mi>n</mi></msup><mo>−</mo><mstyle displaystyle=\"false\" scriptlevel=\"0\"><mfrac><mn>3</mn><mn>2</mn></mfrac></mstyle><msup><mn>2</mn><mi>n</mi></msup><mo>+</mo><mstyle displaystyle=\"false\" scriptlevel=\"0\"><mfrac><mn>5</mn><mn>3</mn></mfrac></mstyle></math> <span>cnot</span> gates, which is less than the best-known exact decomposition algorithm by <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo stretchy=\"false\">(</mo><msup><mn>4</mn><mrow><mi>n</mi><mo>−</mo><mn>2</mn></mrow></msup><mo>−</mo><mn>1</mn><mo stretchy=\"false\">)</mo><mo>/</mo><mn>3</mn></math> <span>cnot</span> gates.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"17 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-09DOI: 10.1103/physrevapplied.22.034018
Thomas Vezin, Hamidreza Esmaielpour, Laurent Lombez, Jean-François Guillemoles, Daniel Suchet
Hot-carrier solar cells offer potential for enhancing the energy-conversion efficiency of photovoltaic devices. Transport properties of such systems remain largely unexplored but could hinder their efficiency. In this work, we develop a suitable framework for describing the thermoelectric ambipolar transport of photogenerated hot carriers and derive analytical expressions for the ambipolar transport coefficients that are valid even in the degenerate case. We demonstrate that these transport coefficients can be measured from hyperspectral photoluminescence imaging. We validate this experimental determination by showing its consistency with the Boltzmann transport equation in the relaxation-time approximation.
{"title":"Optical determination of thermoelectric transport coefficients in a hot-carrier absorber","authors":"Thomas Vezin, Hamidreza Esmaielpour, Laurent Lombez, Jean-François Guillemoles, Daniel Suchet","doi":"10.1103/physrevapplied.22.034018","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.034018","url":null,"abstract":"Hot-carrier solar cells offer potential for enhancing the energy-conversion efficiency of photovoltaic devices. Transport properties of such systems remain largely unexplored but could hinder their efficiency. In this work, we develop a suitable framework for describing the thermoelectric ambipolar transport of photogenerated hot carriers and derive analytical expressions for the ambipolar transport coefficients that are valid even in the degenerate case. We demonstrate that these transport coefficients can be measured from hyperspectral photoluminescence imaging. We validate this experimental determination by showing its consistency with the Boltzmann transport equation in the relaxation-time approximation.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"7 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Sigmoidal curve behavior of 0 and state probability in a magnon parametron, using yttrium iron garnet () thin disk, is systematically investigated. We demonstrate that the probability distribution can be tuned by bias and pump microwave power. Our numerical calculation that considers increasing damping due to four-magnon scattering processes reproduces the results well.
{"title":"Tunable sigmoid behavior of a magnon-based parametron using a Y3Fe5O12/Pt bilayer disk","authors":"Geil Emdi, Tomosato Hioki, Takahiko Makiuchi, Eiji Saitoh","doi":"10.1103/physrevapplied.22.l031002","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.l031002","url":null,"abstract":"Sigmoidal curve behavior of 0 and <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>π</mi></math> state probability in a magnon parametron, using yttrium iron garnet (<math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi mathvariant=\"normal\">Y</mi><mn>3</mn></msub><msub><mi>Fe</mi><mn>5</mn></msub><msub><mi mathvariant=\"normal\">O</mi><mn>12</mn></msub></math>) thin disk, is systematically investigated. We demonstrate that the probability distribution can be tuned by bias and pump microwave power. Our numerical calculation that considers increasing damping due to four-magnon scattering processes reproduces the results well.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"41 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-09DOI: 10.1103/physrevapplied.22.034016
Lina Yang, Yixin Xu, Xianheng Wang, Yanguang Zhou
Tuning thermal transport in nanostructures is essential for many applications, such as thermal management and thermoelectrics. Nanophononic metamaterials (NPMs) have shown great potential for reducing thermal conductivity. In this work, the thermal conductivity of NPMs with crystalline (-) pillar, crystalline (-) pillar, and amorphous (-) pillar are systematically investigated by a molecular dynamics method. An analysis of phonon dispersion and spectral energy density shows that phonon dispersions of a membrane are flattened due to local resonant hybridization induced by both crystalline and amorphous pillars. In addition, an - pillar can cause a larger reduction in thermal conductivity compared with a - pillar. Specifically, when the atomic mass of the atoms in the pillars increases, the thermal conductivity of NPMs with a crystalline pillar increases because of the weakened phonon hybridization. However, the thermal conductivity of NPMs with an amorphous pillar is almost unchanged. The analyses of the reduction of thermal conductivity show that both resonant hybridization and scattering mechanisms are important in NPMs with a crystalline pillar, while the scattering mechanism dominates in NPMs with an amorphous pillar and NPMs with a short crystalline pillar. The results of this work can provide meaningful insights into controlling thermal transport in NPMs by choosing the materials and atomic mass of pillars for specific applications.
{"title":"Tuning the thermal conductivity of a silicon membrane using nanopillars: From crystalline to amorphous pillars","authors":"Lina Yang, Yixin Xu, Xianheng Wang, Yanguang Zhou","doi":"10.1103/physrevapplied.22.034016","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.034016","url":null,"abstract":"Tuning thermal transport in nanostructures is essential for many applications, such as thermal management and thermoelectrics. Nanophononic metamaterials (NPMs) have shown great potential for reducing thermal conductivity. In this work, the thermal conductivity of NPMs with crystalline <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Si</mi></math> (<math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>c</mi></math>-<math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Si</mi></math>) pillar, crystalline <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Ge</mi></math> (<math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>c</mi></math>-<math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Ge</mi></math>) pillar, and amorphous <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Si</mi></math> (<math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>a</mi></math>-<math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Si</mi></math>) pillar are systematically investigated by a molecular dynamics method. An analysis of phonon dispersion and spectral energy density shows that phonon dispersions of a <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Si</mi></math> membrane are flattened due to local resonant hybridization induced by both crystalline and amorphous pillars. In addition, an <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>a</mi></math>-<math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Si</mi></math> pillar can cause a larger reduction in thermal conductivity compared with a <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>c</mi></math>-<math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Si</mi></math> pillar. Specifically, when the atomic mass of the atoms in the pillars increases, the thermal conductivity of NPMs with a crystalline pillar increases because of the weakened phonon hybridization. However, the thermal conductivity of NPMs with an amorphous pillar is almost unchanged. The analyses of the reduction of thermal conductivity show that both resonant hybridization and scattering mechanisms are important in NPMs with a crystalline pillar, while the scattering mechanism dominates in NPMs with an amorphous pillar and NPMs with a short crystalline pillar. The results of this work can provide meaningful insights into controlling thermal transport in NPMs by choosing the materials and atomic mass of pillars for specific applications.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"60 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-06DOI: 10.1103/physrevapplied.22.034015
Peter J. Hobson, Chris Morley, Alister Davis, Thomas Smith, Mark Fromhold
We present a target-field approach to analytically design magnetic fields using permanent magnets. We assume that their magnetization is bound to a two-dimensional surface and is composed of a complete basis of surface modes. By posing the Poisson’s equation relating the magnetic scalar potential to the magnetization using Green’s functions, we derive simple integrals that determine the magnetic field generated by each mode. This approach is demonstrated by deriving the governing integrals for optimizing axial magnetization on cylindrical and circular-planar surfaces. We approximate the governing integrals numerically and implement them into a regularized least-squares optimization routine to design permanent magnets that generate uniform axial and transverse target magnetic fields. The resulting uniform axial magnetic field profiles demonstrate more than a tenfold increase in uniformity across equivalent target regions compared to the field generated by an optimally separated axially magnetized pair of rings, as validated using finite element method simulations. We use a simple example to examine how two-dimensional surface magnetization profiles can be emulated using thin three-dimensional volumes and determine how many discrete intervals are required to accurately approximate a continuously varying surface pattern. Magnets designed using our approach may enable higher-quality bias fields for electric machines, nuclear fusion, fundamental physics, magnetic trapping, and beyond.
{"title":"Target-field design of surface permanent magnets","authors":"Peter J. Hobson, Chris Morley, Alister Davis, Thomas Smith, Mark Fromhold","doi":"10.1103/physrevapplied.22.034015","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.034015","url":null,"abstract":"We present a target-field approach to analytically design magnetic fields using permanent magnets. We assume that their magnetization is bound to a two-dimensional surface and is composed of a complete basis of surface modes. By posing the Poisson’s equation relating the magnetic scalar potential to the magnetization using Green’s functions, we derive simple integrals that determine the magnetic field generated by each mode. This approach is demonstrated by deriving the governing integrals for optimizing axial magnetization on cylindrical and circular-planar surfaces. We approximate the governing integrals numerically and implement them into a regularized least-squares optimization routine to design permanent magnets that generate uniform axial and transverse target magnetic fields. The resulting uniform axial magnetic field profiles demonstrate more than a tenfold increase in uniformity across equivalent target regions compared to the field generated by an optimally separated axially magnetized pair of rings, as validated using finite element method simulations. We use a simple example to examine how two-dimensional surface magnetization profiles can be emulated using thin three-dimensional volumes and determine how many discrete intervals are required to accurately approximate a continuously varying surface pattern. Magnets designed using our approach may enable higher-quality bias fields for electric machines, nuclear fusion, fundamental physics, magnetic trapping, and beyond.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"73 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-05DOI: 10.1103/physrevapplied.22.034014
Carlo Forestiere, Giovanni Miano, Andrea Alù
We derive from first principles a general circuit model for open, frequency dispersive electromagnetic resonators in the full-wave regime. This model extends the concepts of radiation impedance to the polarization current-density modes induced in open resonators by an arbitrary external excitation. Its physics-based elements offer physical insights into the scattering problem and enable efficient modeling of the resonance frequency and associated bandwidth for arbitrary scattering resonances, establishing a powerful platform for the design and optimization of nanophotonic circuits. Our findings offer compelling prospects for electromagnetic scattering and ultrafast nanophotonics, streamlining the analysis and design of nanoresonators with enhanced operational speeds, and outlining a physics-based model of their temporal dynamics.
{"title":"First-principles nanocircuit model of open electromagnetic resonators","authors":"Carlo Forestiere, Giovanni Miano, Andrea Alù","doi":"10.1103/physrevapplied.22.034014","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.034014","url":null,"abstract":"We derive from first principles a general circuit model for open, frequency dispersive electromagnetic resonators in the full-wave regime. This model extends the concepts of radiation impedance to the polarization current-density modes induced in open resonators by an arbitrary external excitation. Its physics-based elements offer physical insights into the scattering problem and enable efficient modeling of the resonance frequency and associated bandwidth for arbitrary scattering resonances, establishing a powerful platform for the design and optimization of nanophotonic circuits. Our findings offer compelling prospects for electromagnetic scattering and ultrafast nanophotonics, streamlining the analysis and design of nanoresonators with enhanced operational speeds, and outlining a physics-based model of their temporal dynamics.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"32 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
We investigate evaporative electron cooling in cascading semiconductor double-quantum-well (QW) structures. In this cascading double QW structure (QW1 and QW2, where QW2 is on the anode side), one electron absorbs two longitudinal optical (LO) phonons as it travels from the cathode to the anode, for which efficient thermionic cooling is expected. By analyzing the high-energy tail of the photoluminescence spectra, the electron temperature in each QW is determined. When barriers are used, anomalous electron heating in QW2 due to hot electron distribution above the barrier is observed. By introducing taller barriers () before QW2 to suppress hot electron distribution above the barrier, electron cooling in both QWs by several tens of kelvins is achieved. Furthermore, oscillatory anticorrelated electron temperature change in the two QWs that results from LO-phonon scattering is observed.
{"title":"Electron cooling behavior in cascading semiconductor double-quantum-well structures","authors":"Xiangyu Zhu, Chloé Salhani, Guéric Etesse, Naomi Nagai, Marc Bescond, Francesca Carosella, Robson Ferreira, Gérald Bastard, Kazuhiko Hirakawa","doi":"10.1103/physrevapplied.22.034012","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.034012","url":null,"abstract":"We investigate evaporative electron cooling in cascading semiconductor double-quantum-well (QW) structures. In this cascading double QW structure (QW1 and QW2, where QW2 is on the anode side), one electron absorbs two longitudinal optical (LO) phonons as it travels from the cathode to the anode, for which efficient thermionic cooling is expected. By analyzing the high-energy tail of the photoluminescence spectra, the electron temperature in each QW is determined. When <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>Al</mi><mrow><mn>0.35</mn></mrow></msub><msub><mi>Ga</mi><mrow><mn>0.65</mn></mrow></msub><mi>As</mi></math> barriers are used, anomalous electron heating in QW2 due to hot electron distribution above the barrier is observed. By introducing taller barriers (<math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>Al</mi><mrow><mn>0.7</mn></mrow></msub><msub><mi>Ga</mi><mrow><mn>0.3</mn></mrow></msub><mi>As</mi></math>) before QW2 to suppress hot electron distribution above the barrier, electron cooling in both QWs by several tens of kelvins is achieved. Furthermore, oscillatory anticorrelated electron temperature change in the two QWs that results from LO-phonon scattering is observed.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"38 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：