The Leidenfrost temperature (), at which the liquid drop lifetime peaks on a superheated surface, is believed to be wettability dependent. Here, we show that the wettability effect on is subject to the history of the surface temperature. Observing a water drop evaporating on a polished stainless-steel surface heated from 100 to in argon gas, we find . We then repeat the experiment along decreasing temperature and find a increase by 10 K, i.e., . This thermal hysteresis is due to a reduced contact angle during heating. Once hydrophilized, the hysteresis disappears until the contact angle recovers. Similar observations are made in the air where oxidation is possible.
{"title":"Thermal hysteresis in wettability and the Leidenfrost phenomenon","authors":"Yutaku Kita, Kensuke Kida, Takaaki Ariyoshi, Sumitomo Hidaka, Masamichi Kohno, Yasuyuki Takata","doi":"10.1103/physrevresearch.6.033287","DOIUrl":"https://doi.org/10.1103/physrevresearch.6.033287","url":null,"abstract":"The Leidenfrost temperature (<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>T</mi><mi>L</mi></msub></math>), at which the liquid drop lifetime peaks on a superheated surface, is believed to be wettability dependent. Here, we show that the wettability effect on <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>T</mi><mi>L</mi></msub></math> is subject to the history of the surface temperature. Observing a water drop evaporating on a polished stainless-steel surface heated from 100 to <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>400</mn><msup><mspace width=\"0.16em\"></mspace><mo>∘</mo></msup><mi mathvariant=\"normal\">C</mi></mrow></math> in argon gas, we find <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>T</mi><mi>L</mi></msub><mo>≈</mo><mn>265</mn><msup><mspace width=\"0.16em\"></mspace><mo>∘</mo></msup><mi mathvariant=\"normal\">C</mi></mrow></math>. We then repeat the experiment along decreasing temperature and find a <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>T</mi><mi>L</mi></msub></math> increase by 10 K, i.e., <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>T</mi><mi>L</mi></msub><mo>≈</mo><mn>275</mn><msup><mspace width=\"0.16em\"></mspace><mo>∘</mo></msup><mi mathvariant=\"normal\">C</mi></mrow></math>. This thermal hysteresis is due to a reduced contact angle during heating. Once hydrophilized, the hysteresis disappears until the contact angle recovers. Similar observations are made in the air where oxidation is possible.","PeriodicalId":20546,"journal":{"name":"Physical Review Research","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142211071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-12DOI: 10.1103/physrevresearch.6.033288
Daniel Fraiman
This paper supports the idea that some out-of-equilibrium systems can be described by universality classes. A specific out-of-equilibrium fusing particles model is studied in detail, resulting in a method for determining the number and mass of the final particles based solely on the initial conditions, eliminating the need to evolve the particle system. This method reveals the basis for a universality class encompassing theorem, which is developed to define other models within the same universality class. This result establishes an infinite number of models with the same behavior and scaling, two of which are described in detail.
{"title":"Universality classes in out-of-equilibrium systems: An encompassing theorem for a one-dimensional fusing particles model","authors":"Daniel Fraiman","doi":"10.1103/physrevresearch.6.033288","DOIUrl":"https://doi.org/10.1103/physrevresearch.6.033288","url":null,"abstract":"This paper supports the idea that some out-of-equilibrium systems can be described by universality classes. A specific out-of-equilibrium fusing particles model is studied in detail, resulting in a method for determining the number and mass of the final particles based solely on the initial conditions, eliminating the need to evolve the particle system. This method reveals the basis for a universality class encompassing theorem, which is developed to define other models within the same universality class. This result establishes an infinite number of models with the same behavior and scaling, two of which are described in detail.","PeriodicalId":20546,"journal":{"name":"Physical Review Research","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142211070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-12DOI: 10.1103/physrevresearch.6.033291
Oleksandr Kyriienko, Annie E. Paine, Vincent E. Elfving
We propose an approach for learning probability distributions as differentiable quantum circuits (DQC) that enable efficient quantum generative modeling (QGM) and synthetic data generation. Contrary to existing QGM approaches, we perform training of a DQC-based model, where data is encoded in a latent space with the proposed phase feature map of exponential capacity. This is followed by a trainable quantum circuit, forming the model. We then map the trained model to the bit basis using a fixed unitary transformation, in this case corresponding to a quantum Fourier transform circuit. It allows fast sampling from parametrized distributions using a single-shot readout. Importantly, latent space training provides models that are automatically differentiable, and we show how samples from solutions of stochastic differential equations (SDEs) can be accessed by solving stationary and time-dependent Fokker-Planck equations with a quantum protocol. Our approach opens a route to multidimensional generative modeling with qubit registers explicitly correlated via a (fixed) entangling layer. In this case quantum computers can offer advantage as efficient samplers, which perform complex inverse transform sampling enabled by the fundamental laws of quantum mechanics. On a technical side the advances are multiple, as we introduce the phase feature map, analyze its properties, and develop frequency-taming techniques that include qubitwise training and feature map sparsification.
{"title":"Protocols for trainable and differentiable quantum generative modeling","authors":"Oleksandr Kyriienko, Annie E. Paine, Vincent E. Elfving","doi":"10.1103/physrevresearch.6.033291","DOIUrl":"https://doi.org/10.1103/physrevresearch.6.033291","url":null,"abstract":"We propose an approach for learning probability distributions as differentiable quantum circuits (DQC) that enable efficient quantum generative modeling (QGM) and synthetic data generation. Contrary to existing QGM approaches, we perform training of a DQC-based model, where data is encoded in a latent space with the proposed phase feature map of exponential capacity. This is followed by a trainable quantum circuit, forming the model. We then map the trained model to the bit basis using a fixed unitary transformation, in this case corresponding to a quantum Fourier transform circuit. It allows fast sampling from parametrized distributions using a single-shot readout. Importantly, latent space training provides models that are automatically differentiable, and we show how samples from solutions of stochastic differential equations (SDEs) can be accessed by solving stationary and time-dependent Fokker-Planck equations with a quantum protocol. Our approach opens a route to multidimensional generative modeling with qubit registers explicitly correlated via a (fixed) entangling layer. In this case quantum computers can offer advantage as efficient samplers, which perform complex inverse transform sampling enabled by the fundamental laws of quantum mechanics. On a technical side the advances are multiple, as we introduce the phase feature map, analyze its properties, and develop frequency-taming techniques that include qubitwise training and feature map sparsification.","PeriodicalId":20546,"journal":{"name":"Physical Review Research","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142211067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Music, enchanting and poetic, permeates every corner of human civilization. Although music is not unfamiliar to people, our understanding of its essence remains limited, and there is still no universally accepted scientific description. This is primarily due to music being regarded as a product of reason and emotion, making it difficult to define. This article treats musical texts as a complex system. This view echoes linguist John Rupert Firth's insight that understanding a word involves defining it through its surrounding relationships. To construct the network we first build a linear regression model with threshold values to assign conditions to the links among note, time, and volume. Then a clustering coefficient representing regional characteristics is utilized to define the word. Finally, the statistical distribution of the text is strictly required to adhere to the grammatical properties of statistical linguistics, such as Zipf's law, to adjust the weights of the linear regression model and achieve optimal results. These processes enable us to comprehend the structural differences in music across different periods with scientific rigor. Relying on the advantages of structuralism, we concentrate on the relationships and order between the physical elements of music, rather than getting entangled in the blurred boundaries of science and philosophy. Aside from serving as a bridge connecting music to natural language processing and knowledge graphs, the technical methods developed in this work offer a more intuitive approach to elucidate the relationships among elements of a complex network.
{"title":"In-depth analysis of music structure as a text network","authors":"Ping-Rui Tsai, Yen-Ting Chou, Nathan-Christopher Wang, Hui-Ling Chen, Hong-Yue Huang, Zih-Jia Luo, Tzay-Ming Hong","doi":"10.1103/physrevresearch.6.033279","DOIUrl":"https://doi.org/10.1103/physrevresearch.6.033279","url":null,"abstract":"Music, enchanting and poetic, permeates every corner of human civilization. Although music is not unfamiliar to people, our understanding of its essence remains limited, and there is still no universally accepted scientific description. This is primarily due to music being regarded as a product of reason and emotion, making it difficult to define. This article treats musical texts as a complex system. This view echoes linguist John Rupert Firth's insight that understanding a word involves defining it through its surrounding relationships. To construct the network we first build a linear regression model with threshold values to assign conditions to the links among note, time, and volume. Then a clustering coefficient representing regional characteristics is utilized to define the word. Finally, the statistical distribution of the text is strictly required to adhere to the grammatical properties of statistical linguistics, such as Zipf's law, to adjust the weights of the linear regression model and achieve optimal results. These processes enable us to comprehend the structural differences in music across different periods with scientific rigor. Relying on the advantages of structuralism, we concentrate on the relationships and order between the physical elements of music, rather than getting entangled in the blurred boundaries of science and philosophy. Aside from serving as a bridge connecting music to natural language processing and knowledge graphs, the technical methods developed in this work offer a more intuitive approach to elucidate the relationships among elements of a complex network.","PeriodicalId":20546,"journal":{"name":"Physical Review Research","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142211106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1103/physrevresearch.6.033282
Alice Pagano, Daniel Jaschke, Werner Weiss, Simone Montangero
The transport of neutral atoms in Rydberg quantum computers is a crucial step for the initial arrangement of the grid as well as the dynamic connectivity, recently successfully demonstrated. We study the application of optimal control and the quantum speed limit for the transport of neutral atoms in optical tweezers at finite temperatures and analyze how laser noise affects transport fidelity. Open-loop optimal control significantly enhances transport fidelity, achieving an improvement up to 89% for the lowest analyzed temperature of for a distance of . Furthermore, we simulate how the transport fidelity behaves in release-and-capture measurements, which are realizable in the experiment to estimate transport efficiency and implement closed-loop optimal control.
{"title":"Optimal control transport of neutral atoms in optical tweezers at finite temperature","authors":"Alice Pagano, Daniel Jaschke, Werner Weiss, Simone Montangero","doi":"10.1103/physrevresearch.6.033282","DOIUrl":"https://doi.org/10.1103/physrevresearch.6.033282","url":null,"abstract":"The transport of neutral atoms in Rydberg quantum computers is a crucial step for the initial arrangement of the grid as well as the dynamic connectivity, recently successfully demonstrated. We study the application of optimal control and the quantum speed limit for the transport of neutral atoms in optical tweezers at finite temperatures and analyze how laser noise affects transport fidelity. Open-loop optimal control significantly enhances transport fidelity, achieving an improvement up to 89% for the lowest analyzed temperature of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>1</mn><mspace width=\"0.16em\"></mspace><mo>µ</mo><mi mathvariant=\"normal\">K</mi></mrow></math> for a distance of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>3</mn><mspace width=\"0.16em\"></mspace><mo>µ</mo><mi mathvariant=\"normal\">m</mi></mrow></math>. Furthermore, we simulate how the transport fidelity behaves in release-and-capture measurements, which are realizable in the experiment to estimate transport efficiency and implement closed-loop optimal control.","PeriodicalId":20546,"journal":{"name":"Physical Review Research","volume":"229 5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142211100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1103/physrevresearch.6.033280
Ya-Dong Wu, Yan Zhu, Giulio Chiribella, Nana Liu
The characterization of continuous-variable quantum states is crucial for applications in quantum communication, sensing, simulation, and computing. However, a full characterization of multimode quantum states requires a number of experiments that grows exponentially with the number of modes. Here we propose an alternative approach where the goal is not to reconstruct the full quantum state, but rather to estimate its characteristic function at a given set of points. For multimode states with reflection symmetry, we show that the characteristic function at points can be estimated using only copies of the state, independently of the number of modes. When the characteristic function is known to be positive, as in the case of squeezed vacuum states, the estimation is achieved by an experimentally friendly setup using only beamsplitters and homodyne measurements.
连续可变量子态的表征对于量子通信、传感、模拟和计算领域的应用至关重要。然而，要对多模量子态进行全面表征，需要进行大量实验，而实验数量会随着模数的增加呈指数增长。在这里，我们提出了一种替代方法，其目标不是重建完整的量子态，而是估算其在给定点上的特征函数。对于具有反射对称性的多模态，我们证明只需使用 O(logM) 份状态副本就能估算出 M 个点上的特征函数，而与模数无关。当已知特征函数为正时，如在挤压真空态的情况下，只需使用分光镜和同调测量，就能通过实验友好型装置实现估算。
{"title":"Efficient learning of continuous-variable quantum states","authors":"Ya-Dong Wu, Yan Zhu, Giulio Chiribella, Nana Liu","doi":"10.1103/physrevresearch.6.033280","DOIUrl":"https://doi.org/10.1103/physrevresearch.6.033280","url":null,"abstract":"The characterization of continuous-variable quantum states is crucial for applications in quantum communication, sensing, simulation, and computing. However, a full characterization of multimode quantum states requires a number of experiments that grows exponentially with the number of modes. Here we propose an alternative approach where the goal is not to reconstruct the full quantum state, but rather to estimate its characteristic function at a given set of points. For multimode states with reflection symmetry, we show that the characteristic function at <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>M</mi></math> points can be estimated using only <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>O</mi><mo>(</mo><mo form=\"prefix\">log</mo><mi>M</mi><mo>)</mo></mrow></math> copies of the state, independently of the number of modes. When the characteristic function is known to be positive, as in the case of squeezed vacuum states, the estimation is achieved by an experimentally friendly setup using only beamsplitters and homodyne measurements.","PeriodicalId":20546,"journal":{"name":"Physical Review Research","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142211107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Quantum teleportation is widely applied as a key ingredient in quantum information science, and quantum network provides unique abilities for upscaling its applications. Polarization state of light is a vital degree of freedom with the advantages of remote transfer and direct light-atom interaction. To construct a multiuser quantum network, deterministic quantum teleportation of polarization state in more users' network remains challenging. Compared with photonic quantum state, the deterministic quantum teleportation network of polarization state is realized with a single set of continuous-variable entangled states. The key techniques include only one set of quadrature entangled network, single quadrature controller, and active polarization controller. Arbitrary polarization state is deterministically and controllably teleported in such a system involving four or three users. This system is deterministic and scalable with user number, which enables the potential application in deterministic metropolitan quantum network.
{"title":"Deterministic and multiuser quantum teleportation network of continuous-variable polarization states","authors":"Jieli Yan, Xiaoyu Zhou, Yue Qin, Zhihui Yan, Xiaojun Jia, Changde Xie, Kunchi Peng","doi":"10.1103/physrevresearch.6.l032062","DOIUrl":"https://doi.org/10.1103/physrevresearch.6.l032062","url":null,"abstract":"Quantum teleportation is widely applied as a key ingredient in quantum information science, and quantum network provides unique abilities for upscaling its applications. Polarization state of light is a vital degree of freedom with the advantages of remote transfer and direct light-atom interaction. To construct a multiuser quantum network, deterministic quantum teleportation of polarization state in more users' network remains challenging. Compared with photonic quantum state, the deterministic quantum teleportation network of polarization state is realized with a single set of continuous-variable entangled states. The key techniques include only one set of quadrature entangled network, single quadrature controller, and active polarization controller. Arbitrary polarization state is deterministically and controllably teleported in such a system involving four or three users. This system is deterministic and scalable with user number, which enables the potential application in deterministic metropolitan quantum network.","PeriodicalId":20546,"journal":{"name":"Physical Review Research","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142211098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1103/physrevresearch.6.033283
Matteo Castagnola, Marcus T. Lexander, Enrico Ronca, Henrik Koch
We analyze the real-time electron-photon dynamics in long- and short-range energy transfer using a real-time quantum electrodynamics coupled cluster model, which allows for spatial and temporal visualization of transport processes. We compute the time evolution of photonic and molecular observables, such as the dipole moment and the photon coordinate, following the excitation of the system induced by short laser pulses. Our simulations show that intermolecular interactions and light-matter strong coupling lead to modified electronic polarization compared to the undressed molecules. The developed method can simulate multiple high-intensity laser pulses while explicitly retaining electronic and electron-photon correlation and is thus suited for nonlinear optics and transient absorption spectroscopies of molecular polaritons.
{"title":"Strong coupling electron-photon dynamics: A real-time investigation of energy redistribution in molecular polaritons","authors":"Matteo Castagnola, Marcus T. Lexander, Enrico Ronca, Henrik Koch","doi":"10.1103/physrevresearch.6.033283","DOIUrl":"https://doi.org/10.1103/physrevresearch.6.033283","url":null,"abstract":"We analyze the real-time electron-photon dynamics in long- and short-range energy transfer using a real-time quantum electrodynamics coupled cluster model, which allows for spatial and temporal visualization of transport processes. We compute the time evolution of photonic and molecular observables, such as the dipole moment and the photon coordinate, following the excitation of the system induced by short laser pulses. Our simulations show that intermolecular interactions and light-matter strong coupling lead to modified electronic polarization compared to the undressed molecules. The developed method can simulate multiple high-intensity laser pulses while explicitly retaining electronic and electron-photon correlation and is thus suited for nonlinear optics and transient absorption spectroscopies of molecular polaritons.","PeriodicalId":20546,"journal":{"name":"Physical Review Research","volume":"80 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142211099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1103/physrevresearch.6.033281
Axel Leblanc, Chotivut Tangchingchai, Zahra Sadre Momtaz, Elyjah Kiyooka, Jean-Michel Hartmann, Gonzalo Troncoso Fernandez-Bada, Zoltán Scherübl, Boris Brun, Vivien Schmitt, Simon Zihlmann, Romain Maurand, Étienne Dumur, Silvano De Franceschi, François Lefloch
Hybrid superconductor(S)-semiconductor(Sm) devices bring a range of functionalities into superconducting circuits. In particular, hybrid parity-protected qubits and Josephson diodes were recently proposed and experimentally demonstrated. Such devices leverage the nonsinusoidal character of the Josephson current-phase relation (CPR) in highly transparent S-Sm-S junctions. Here, we report an experimental study of superconducting quantum-interference devices (SQUIDs) embedding Josephson field-effect transistors fabricated from a SiGe/Ge/SiGe heterostructure grown on a 200-mm silicon wafer. The single-junction CPR shows up to three harmonics with gate-tunable amplitude. In the presence of microwave irradiation, the ratio of the first two dominant harmonics, corresponding to single and double Cooper-pair transport processes, is consistently reflected in relative weight of integer and half-integer Shapiro steps. A combination of magnetic-flux and gate-voltage control enables tuning the SQUID functionality from a nonreciprocal Josephson-diode regime with 27% asymmetry to a -periodic Josephson regime suitable for the implementation of parity-protected superconducting qubits. These results illustrate the potential of Ge-based hybrid devices as versatile and scalable building blocks of superconducting quantum circuits.
{"title":"From nonreciprocal to charge-4e supercurrent in Ge-based Josephson devices with tunable harmonic content","authors":"Axel Leblanc, Chotivut Tangchingchai, Zahra Sadre Momtaz, Elyjah Kiyooka, Jean-Michel Hartmann, Gonzalo Troncoso Fernandez-Bada, Zoltán Scherübl, Boris Brun, Vivien Schmitt, Simon Zihlmann, Romain Maurand, Étienne Dumur, Silvano De Franceschi, François Lefloch","doi":"10.1103/physrevresearch.6.033281","DOIUrl":"https://doi.org/10.1103/physrevresearch.6.033281","url":null,"abstract":"Hybrid superconductor(S)-semiconductor(Sm) devices bring a range of functionalities into superconducting circuits. In particular, hybrid parity-protected qubits and Josephson diodes were recently proposed and experimentally demonstrated. Such devices leverage the nonsinusoidal character of the Josephson current-phase relation (CPR) in highly transparent S-Sm-S junctions. Here, we report an experimental study of superconducting quantum-interference devices (SQUIDs) embedding Josephson field-effect transistors fabricated from a SiGe/Ge/SiGe heterostructure grown on a 200-mm silicon wafer. The single-junction CPR shows up to three harmonics with gate-tunable amplitude. In the presence of microwave irradiation, the ratio of the first two dominant harmonics, corresponding to single and double Cooper-pair transport processes, is consistently reflected in relative weight of integer and half-integer Shapiro steps. A combination of magnetic-flux and gate-voltage control enables tuning the SQUID functionality from a nonreciprocal Josephson-diode regime with 27% asymmetry to a <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>π</mi></math>-periodic Josephson regime suitable for the implementation of parity-protected superconducting qubits. These results illustrate the potential of Ge-based hybrid devices as versatile and scalable building blocks of superconducting quantum circuits.","PeriodicalId":20546,"journal":{"name":"Physical Review Research","volume":"177 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142211102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","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/physrevresearch.6.033278
Madhuchhanda Brahma, Maarten L. Van de Put, Edward Chen, Massimo V. Fischetti, William G. Vandenberghe
In this theoretical study, we compare electrostatically doped metal-transition metal dichalcogenide (TMD) edge-contacts versus substitutionally doped edge-contacts in terms of their contact resistance. Our approach involves the utilization of electrostatic doping achieved by applying back-gate bias to the metal-TMD edge contacts, where carrier injection is primarily governed by the Schottky barrier at the interface. To analyze these contacts, we employ the Wentzel-Kramers-Brillouin (WKB) approximation to calculate the transmission coefficient and use density functional theory (DFT)-derived band structures. We numerically solve the Poisson equation to capture the electrostatic potential. We also account for the impact of the image force using Green's function for the Poisson equation with boundary conditions appropriate to our specific geometry. Our findings reveal that electrostatically doped TMD edge contacts exhibit higher contact resistance compared to impurity-doped edge contacts at equivalent carrier concentrations. At the same time, we find that, among the electrostatically doped edge contacts, a low- back-gate oxide in conjunction with low- top oxide is preferable in terms of improvement in contact resistance. For instance, in a metal-TMD edge contact scenario involving a monolayer as the channel, as the infinitely thick top oxide, and a back-gate oxide with an equivalent oxide thickness (EOT) of , we demonstrate that it is possible to achieve an impressively low contact resistance of when the back-gate bias exceeds or equals 2 V.
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