Pub Date : 2024-09-13DOI: 10.1103/physrevapplied.22.034036
Philipp Bredol, Felix David, Nagesh S. Jagtap, Yannick S. Klaß, Georgy V. Astakhov, Artur Erbe, Eva M. Weig
Hybrid quantum devices enable novel functionalities by combining the benefits of different subsystems. Particularly, point defects in nanomechanical resonators made of diamond or silicon carbide (SiC) have been proposed for precise magnetic field sensing and as versatile quantum transducers. However, the realization of a hybrid system may involve trade-offs in the performance of the constituent subsystems. In a spin-mechanical system, the mechanical properties of the resonator may suffer from the presence of engineered defects in the crystal lattice. This may severely restrict the performance of the resulting device and needs to be carefully explored. Here we focus on the impact of defects on high- nanomechanical string resonators made of prestressed -SiC grown on Si(111). We use helium-ion implantation to create point defects and study their accumulated effect on the mechanical performance. Using Euler-Bernoulli beam theory, we present a method to determine Young’s modulus and the prestress of the strings. We find that Young’s modulus is not modified by implantation. Under implantation doses relevant for single-defect or defect-ensemble generation, both tensile stress and damping rate also remain unaltered. For a higher implantation dose, both exhibit a characteristic change.
{"title":"Effect of helium-ion implantation on 3C-SiC nanomechanical string resonators","authors":"Philipp Bredol, Felix David, Nagesh S. Jagtap, Yannick S. Klaß, Georgy V. Astakhov, Artur Erbe, Eva M. Weig","doi":"10.1103/physrevapplied.22.034036","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.034036","url":null,"abstract":"Hybrid quantum devices enable novel functionalities by combining the benefits of different subsystems. Particularly, point defects in nanomechanical resonators made of diamond or silicon carbide (SiC) have been proposed for precise magnetic field sensing and as versatile quantum transducers. However, the realization of a hybrid system may involve trade-offs in the performance of the constituent subsystems. In a spin-mechanical system, the mechanical properties of the resonator may suffer from the presence of engineered defects in the crystal lattice. This may severely restrict the performance of the resulting device and needs to be carefully explored. Here we focus on the impact of defects on high-<math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Q</mi></math> nanomechanical string resonators made of prestressed <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mn>3</mn><mi>C</mi></math>-SiC grown on Si(111). We use helium-ion implantation to create point defects and study their accumulated effect on the mechanical performance. Using Euler-Bernoulli beam theory, we present a method to determine Young’s modulus and the prestress of the strings. We find that Young’s modulus is not modified by implantation. Under implantation doses relevant for single-defect or defect-ensemble generation, both tensile stress and damping rate also remain unaltered. For a higher implantation dose, both exhibit a characteristic change.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"36 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185325","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 : 2024-09-13DOI: 10.1103/physrevapplied.22.034035
Alec Yen, Yufeng Ye, Kaidong Peng, Jennifer Wang, Gregory Cunningham, Michael Gingras, Bethany M. Niedzielski, Hannah Stickler, Kyle Serniak, Mollie E. Schwartz, Kevin P. O’Brien
We propose and demonstrate transmission-based dispersive readout of a superconducting qubit using an all-pass resonator, which preferentially emits readout photons toward the output. This is in contrast to typical readout schemes, which intentionally mismatch the feedline at one end so that the readout signal preferentially decays toward the output. We show that this intentional mismatch creates scaling challenges, including larger spread of effective resonator linewidths due to nonideal impedance environments and added infrastructure for impedance matching. A future architecture using multiplexed all-pass readout resonators would avoid the need for intentional mismatch and potentially improve the scaling prospects of quantum computers. As a proof-of-concept demonstration of “all-pass readout,” we design and fabricate an all-pass readout resonator that demonstrates insertion loss below 1.17 dB at the readout frequency and a maximum insertion loss of 1.53 dB across its full bandwidth for the lowest three states of a transmon qubit. We demonstrate qubit readout with an average single-shot fidelity of 98.1% in 600 ns; to assess the effect of larger dispersive shift, we implement a shelving protocol and achieve a fidelity of 99.0% in 300 ns.
{"title":"Directional emission of a readout resonator for qubit measurement","authors":"Alec Yen, Yufeng Ye, Kaidong Peng, Jennifer Wang, Gregory Cunningham, Michael Gingras, Bethany M. Niedzielski, Hannah Stickler, Kyle Serniak, Mollie E. Schwartz, Kevin P. O’Brien","doi":"10.1103/physrevapplied.22.034035","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.034035","url":null,"abstract":"We propose and demonstrate transmission-based dispersive readout of a superconducting qubit using an all-pass resonator, which preferentially emits readout photons toward the output. This is in contrast to typical readout schemes, which intentionally mismatch the feedline at one end so that the readout signal preferentially decays toward the output. We show that this intentional mismatch creates scaling challenges, including larger spread of effective resonator linewidths due to nonideal impedance environments and added infrastructure for impedance matching. A future architecture using multiplexed all-pass readout resonators would avoid the need for intentional mismatch and potentially improve the scaling prospects of quantum computers. As a proof-of-concept demonstration of “all-pass readout,” we design and fabricate an all-pass readout resonator that demonstrates insertion loss below 1.17 dB at the readout frequency and a maximum insertion loss of 1.53 dB across its full bandwidth for the lowest three states of a transmon qubit. We demonstrate qubit readout with an average single-shot fidelity of 98.1% in 600 ns; to assess the effect of larger dispersive shift, we implement a shelving protocol and achieve a fidelity of 99.0% in 300 ns.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"6 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185326","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 : 2024-09-13DOI: 10.1103/physrevapplied.22.034037
Ryunosuke Hayashi, Shoki Nezu, Koji Sekiguchi
This work presents a significant advancement in spin-wave computing devices utilizing magnetostatic surface spin waves. We demonstrate a micro-Y-shaped waveguide fabricated from yttrium iron garnet with a nanometer thickness. This intricately engineered design enables a novel logic device with two inputs and one output, enabling future cascading of such elements. Electrical measurements on the Y-shaped structure reveal that strategically introduced gaps effectively manipulate spin-wave propagation, as corroborated by detailed micromagnetic simulations. Notably, we achieve robust diagonal spin-wave transmission across 1.2 µm gaps, covering a distance of 120 µm. Furthermore, the gapped device exhibits clear phase-dependent spin-wave interference, surpassing the performance of a conventional Y-shaped design. This phenomenon, confirmed by mapping simulated magnetization components, signifies the potential of dipole-coupled devices for realizing efficient 2-input-1-output magnonic logic elements, laying the groundwork for future development in this field.
这项工作展示了利用磁静力表面自旋波的自旋波计算设备的重大进展。我们展示了用纳米厚度的钇铁石榴石制造的微型 Y 形波导。这种复杂的工程设计实现了一种具有两个输入和一个输出的新型逻辑器件，使未来此类元件的级联成为可能。对 Y 型结构进行的电学测量显示，策略性引入的间隙能有效操纵自旋波的传播，详细的微磁模拟也证实了这一点。值得注意的是，我们实现了跨越 1.2 微米间隙、覆盖 120 微米距离的强劲对角线自旋波传输。此外，间隙器件还表现出明显的相位自旋波干涉，性能超过了传统的 Y 型设计。这一现象通过绘制模拟磁化分量图得到证实，表明偶极耦合器件具有实现高效 2 输入 1 输出磁性逻辑元件的潜力，为这一领域的未来发展奠定了基础。
{"title":"Enhanced signal-to-noise ratio in magnonic logic gates via dipole coupling","authors":"Ryunosuke Hayashi, Shoki Nezu, Koji Sekiguchi","doi":"10.1103/physrevapplied.22.034037","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.034037","url":null,"abstract":"This work presents a significant advancement in spin-wave computing devices utilizing magnetostatic surface spin waves. We demonstrate a micro-<span>Y</span>-shaped waveguide fabricated from yttrium iron garnet with a nanometer thickness. This intricately engineered design enables a novel logic device with two inputs and one output, enabling future cascading of such elements. Electrical measurements on the <span>Y</span>-shaped structure reveal that strategically introduced gaps effectively manipulate spin-wave propagation, as corroborated by detailed micromagnetic simulations. Notably, we achieve robust diagonal spin-wave transmission across 1.2 µm gaps, covering a distance of 120 µm. Furthermore, the gapped device exhibits clear phase-dependent spin-wave interference, surpassing the performance of a conventional <span>Y</span>-shaped design. This phenomenon, confirmed by mapping simulated magnetization components, signifies the potential of dipole-coupled devices for realizing efficient 2-input-1-output magnonic logic elements, laying the groundwork for future development in this field.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"9 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224185","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 : 2024-09-12DOI: 10.1103/physrevapplied.22.034031
Yi-Ming Ding, Yan-Cheng Wang, Shi-Xin Zhang, Zheng Yan
Optimization problems are the core challenge in many fields of science and engineering, yet general and effective methods for finding optimal solutions remain scarce. Quantum computing has been envisioned to help solve such problems, with methods like quantum annealing (QA), grounded in adiabatic evolution, being extensively explored and successfully implemented on quantum simulators such as D-Wave’s annealers and some Rydberg arrays. In this work, we investigate the topological sector optimization (TSO) problem, which has attracted particular interest in the quantum simulation and many-body physics community. We reveal that the topology induced by frustration in the optimization model is an intrinsic obstruction for QA and other traditional methods to approach the ground state. We demonstrate that the difficulties of the TSO problem are not restricted to the gaplessness, but are also due to the topological nature, which was often ignored for the analysis of optimization problems before. To solve TSO problems, we utilize quantum imaginary-time evolution (QITE) with a possible realization on quantum computers, which leverages the property of quantum superposition to explore the full Hilbert space and can thus address optimization problems of topological nature. We report the performance of different quantum optimization algorithms on TSO problems and demonstrate that their capabilities to address optimization problems are distinct even when considering the quantum computational resources required for practical QITE implementations.
{"title":"Exploring the topological sector optimization on quantum computers","authors":"Yi-Ming Ding, Yan-Cheng Wang, Shi-Xin Zhang, Zheng Yan","doi":"10.1103/physrevapplied.22.034031","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.034031","url":null,"abstract":"Optimization problems are the core challenge in many fields of science and engineering, yet general and effective methods for finding optimal solutions remain scarce. Quantum computing has been envisioned to help solve such problems, with methods like quantum annealing (QA), grounded in adiabatic evolution, being extensively explored and successfully implemented on quantum simulators such as D-Wave’s annealers and some Rydberg arrays. In this work, we investigate the topological sector optimization (TSO) problem, which has attracted particular interest in the quantum simulation and many-body physics community. We reveal that the topology induced by frustration in the optimization model is an intrinsic obstruction for QA and other traditional methods to approach the ground state. We demonstrate that the difficulties of the TSO problem are not restricted to the gaplessness, but are also due to the topological nature, which was often ignored for the analysis of optimization problems before. To solve TSO problems, we utilize quantum imaginary-time evolution (QITE) with a possible realization on quantum computers, which leverages the property of quantum superposition to explore the full Hilbert space and can thus address optimization problems of topological nature. We report the performance of different quantum optimization algorithms on TSO problems and demonstrate that their capabilities to address optimization problems are distinct even when considering the quantum computational resources required for practical QITE implementations.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"300 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185205","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 : 2024-09-12DOI: 10.1103/physrevapplied.22.034029
Jonas Homrighausen, Frederik Hoffmann, Jens Pogorzelski, Peter Glösekötter, Markus Gregor
In quantum sensing of magnetic fields, ensembles of nitrogen-vacancy centers in diamond offer high sensitivity, high bandwidth and outstanding spatial resolution while operating in harsh environments. Moreover, the orientation of defect centers along four crystal axes forms an intrinsic coordinate system, enabling vector magnetometry within a single diamond crystal. While most vector magnetometers rely on a known bias magnetic field for full recovery of three-dimensional (3D) field information, employing external 3D Helmholtz coils or permanent magnets results in bulky, laboratory-bound setups, impeding miniaturization of the device. Here, a novel approach is presented that utilizes a fiber-integrated microscale coil at the fiber tip to generate a localized uniaxial magnetic field. The same fiber-tip coil is used in parallel for spin control by combining dc and microwave signals in a bias tee. To implement vector magnetometry using a uniaxial bias field, the orientation of the diamond crystal is preselected and then fully characterized by rotating a static magnetic field in three planes of rotation. The measurement of vector magnetic fields in the full solid angle is demonstrated with a shot-noise-limited sensitivity of and microscale spatial resolution while achieving a fiber sensor head cross section of less than .
{"title":"Microscale fiber-integrated vector magnetometer with on-tip field biasing using N-V ensembles in diamond microcrystals","authors":"Jonas Homrighausen, Frederik Hoffmann, Jens Pogorzelski, Peter Glösekötter, Markus Gregor","doi":"10.1103/physrevapplied.22.034029","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.034029","url":null,"abstract":"In quantum sensing of magnetic fields, ensembles of nitrogen-vacancy centers in diamond offer high sensitivity, high bandwidth and outstanding spatial resolution while operating in harsh environments. Moreover, the orientation of defect centers along four crystal axes forms an intrinsic coordinate system, enabling vector magnetometry within a single diamond crystal. While most vector magnetometers rely on a known bias magnetic field for full recovery of three-dimensional (3D) field information, employing external 3D Helmholtz coils or permanent magnets results in bulky, laboratory-bound setups, impeding miniaturization of the device. Here, a novel approach is presented that utilizes a fiber-integrated microscale coil at the fiber tip to generate a localized uniaxial magnetic field. The same fiber-tip coil is used in parallel for spin control by combining dc and microwave signals in a bias tee. To implement vector magnetometry using a uniaxial bias field, the orientation of the diamond crystal is preselected and then fully characterized by rotating a static magnetic field in three planes of rotation. The measurement of vector magnetic fields in the full solid angle is demonstrated with a shot-noise-limited sensitivity of <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mn>19.4</mn><mspace width=\"0.2em\"></mspace><msup><mtext>nT/Hz</mtext><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup></math> and microscale spatial resolution while achieving a fiber sensor head cross section of less than <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mn>1</mn><mspace width=\"0.2em\"></mspace><msup><mtext>mm</mtext><mn>2</mn></msup></math>.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"62 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224188","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 : 2024-09-12DOI: 10.1103/physrevapplied.22.034028
Sahitya V. Vegesna, Venkata Rao Rayapati, Heidemarie Schmidt
Interface-type, analog memristors have quite a reputation for real-time applications in edge sensorics, edge computing, and neuromorphic computing. The n-type conducting (BFO) is such an interface-type, analog memristor, which is also nonlinear and can therefore not only store, but also process data in the same memristor cell without data transfer between the data-storage unit and the data-processing unit. Here we present a physical memristor model, which describes the hysteretic current-voltage curves of the BFO memristor in the small and large current-voltage range. Extracted internal state variables are reconfigured by the ion drift in the two write branches and are determining the electron transport in the two read branches. Simulation of electronic circuits with the BFO interface-type, analog memristors was not possible so far because previous physical memristor models have not captured the full range of internal state variables. We show quantitative agreement between modeled and experimental current-voltage curves exemplarily of three different BFO memristors in the small and large current-voltage ranges. Extracted dynamic and static internal state variables in the two full write branches and in the two full read branches, respectively, can be used for simulating electronic circuits with BFO memristors, e.g., in edge sensorics, edge computing, and neuromorphic computing.
{"title":"Transport properties of interface-type analog memristors","authors":"Sahitya V. Vegesna, Venkata Rao Rayapati, Heidemarie Schmidt","doi":"10.1103/physrevapplied.22.034028","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.034028","url":null,"abstract":"Interface-type, analog memristors have quite a reputation for real-time applications in edge sensorics, edge computing, and neuromorphic computing. The <i>n</i>-type conducting <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mrow><mi>Bi</mi><mi>Fe</mi><mi mathvariant=\"normal\">O</mi></mrow><mn>3</mn></msub></math> (BFO) is such an interface-type, analog memristor, which is also nonlinear and can therefore not only store, but also process data in the same memristor cell without data transfer between the data-storage unit and the data-processing unit. Here we present a physical memristor model, which describes the hysteretic current-voltage curves of the BFO memristor in the small and large current-voltage range. Extracted internal state variables are reconfigured by the ion drift in the two write branches and are determining the electron transport in the two read branches. Simulation of electronic circuits with the BFO interface-type, analog memristors was not possible so far because previous physical memristor models have not captured the full range of internal state variables. We show quantitative agreement between modeled and experimental current-voltage curves exemplarily of three different BFO memristors in the small and large current-voltage ranges. Extracted dynamic and static internal state variables in the two full write branches and in the two full read branches, respectively, can be used for simulating electronic circuits with BFO memristors, e.g., in edge sensorics, edge computing, and neuromorphic computing.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"1 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224190","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 : 2024-09-12DOI: 10.1103/physrevapplied.22.034030
Hengyan Wang, Michael Zugenmaier, Kasper Jensen, Wenqiang Zheng, Eugene S. Polzik
We propose and demonstrate a combined static- and oscillating-field alkali atom magnetometer and use it as a magnetic induction tomography sensor. The magnetometer realizes simultaneous measurements of the static and oscillating magnetic fields using two different Zeeman transitions of a single sensor. This approach dramatically enhances the long-term stability and sensitivity of detection of low-conductivity objects. Using our dual-frequency magnetometer, we detect small containers with salt water with conductivity as low as 0.55 S/m. We achieved a conductivity measurement uncertainty of 0.18 S/m with a 10-s integration time. This performance is sufficient to distinguish between healthy and malignant tissue in the human body. The dual-frequency magnetometer can also be used as a self-stabilized radio-frequency magnetometer.
{"title":"Magnetic induction sensor based on a dual-frequency atomic magnetometer","authors":"Hengyan Wang, Michael Zugenmaier, Kasper Jensen, Wenqiang Zheng, Eugene S. Polzik","doi":"10.1103/physrevapplied.22.034030","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.034030","url":null,"abstract":"We propose and demonstrate a combined static- and oscillating-field alkali atom magnetometer and use it as a magnetic induction tomography sensor. The magnetometer realizes simultaneous measurements of the static and oscillating magnetic fields using two different Zeeman transitions of a single sensor. This approach dramatically enhances the long-term stability and sensitivity of detection of low-conductivity objects. Using our dual-frequency magnetometer, we detect small containers with salt water with conductivity as low as 0.55 S/m. We achieved a conductivity measurement uncertainty of 0.18 S/m with a 10-s integration time. This performance is sufficient to distinguish between healthy and malignant tissue in the human body. The dual-frequency magnetometer can also be used as a self-stabilized radio-frequency magnetometer.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"5 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224189","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 : 2024-09-12DOI: 10.1103/physrevapplied.22.034033
Claudio E. Calosso, Michele Gozzelino, Filippo Levi, Salvatore Micalizio
This paper describes the light-shift laser-lock (LSLL) technique, an alternative method intended for laser-based compact atomic clocks. The technique greatly simplifies the laser setup by stabilizing the pumping-laser frequency to the same atoms involved in the clock operation, without the need of an external reference. By alternating two clock sequences, the method estimates and cancels out a controlled amount of induced light shift, acting on the laser frequency. The LSLL technique is compatible with state-of-the-art three-level clocks and was demonstrated with field-programmable-gate-array-based electronics on a pulsed-optically-pumped vapor-cell clock developed at INRIM. The results have shown that the LSLL technique operates robustly, having a capture range of gigahertz without significantly compromising clock stability. In our tests, the clock exhibited a white frequency noise of for averaging times up to 4000 s, reaching a floor below 1× up to 100 000 s. This level of performance meets the requirements of future global navigation satellite systems on-board clocks, adding the benefits of a reduced clock footprint, as well as increased reliability and robustness.
{"title":"Laser-frequency stabilization using light shift in compact atomic clocks","authors":"Claudio E. Calosso, Michele Gozzelino, Filippo Levi, Salvatore Micalizio","doi":"10.1103/physrevapplied.22.034033","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.034033","url":null,"abstract":"This paper describes the light-shift laser-lock (LSLL) technique, an alternative method intended for laser-based compact atomic clocks. The technique greatly simplifies the laser setup by stabilizing the pumping-laser frequency to the same atoms involved in the clock operation, without the need of an external reference. By alternating two clock sequences, the method estimates and cancels out a controlled amount of induced light shift, acting on the laser frequency. The LSLL technique is compatible with state-of-the-art three-level clocks and was demonstrated with field-programmable-gate-array-based electronics on a pulsed-optically-pumped vapor-cell clock developed at INRIM. The results have shown that the LSLL technique operates robustly, having a capture range of gigahertz without significantly compromising clock stability. In our tests, the clock exhibited a white frequency noise of <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mn>3.2</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>13</mn></mrow></msup><msup><mi>τ</mi><mrow><mo>−</mo><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup></math> for averaging times <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>τ</mi></math> up to 4000 s, reaching a floor below 1×<math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mn>10</mn><mrow><mo>−</mo><mn>14</mn></mrow></msup></math> up to 100 000 s. This level of performance meets the requirements of future global navigation satellite systems on-board clocks, adding the benefits of a reduced clock footprint, as well as increased reliability and robustness.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"184 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224187","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 : 2024-09-12DOI: 10.1103/physrevapplied.22.034032
Ivan S. Sushchev, Daniil S. Bulavkin, Kirill E. Bugai, Anna S. Sidelnikova, Dmitriy A. Dvoretskiy
This paper presents a theoretical and experimental demonstration of a security analysis of a Trojan-horse attack (THA) on a real-world quantum key distribution (QKD) system. We show that the upper bound on the information leakage depends solely on the fidelity between the states of the adversary. We find the lower bound for fidelity between THA states in both the polarization- and phase-coding BB84 protocols, considering both pure and mixed states. Our bounds depend only on the mean photon number per pulse available to an adversary. We also present an experimental analysis of a QKD system, including optical time-domain reflectometry measurements with centimeter resolution and spectral transmittance measurements for optical defense elements ranging from 1100 to 1800 nm with a noise floor lower than dB. Finally, by considering the optimal attack, we obtain the value of the mean photon number per pulse available to an adversary and calculate the key leakage that needs to be eliminated during the privacy amplification procedure.
{"title":"Trojan-horse attack on a real-world quantum key distribution system: Theoretical and experimental security analysis","authors":"Ivan S. Sushchev, Daniil S. Bulavkin, Kirill E. Bugai, Anna S. Sidelnikova, Dmitriy A. Dvoretskiy","doi":"10.1103/physrevapplied.22.034032","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.034032","url":null,"abstract":"This paper presents a theoretical and experimental demonstration of a security analysis of a Trojan-horse attack (THA) on a real-world quantum key distribution (QKD) system. We show that the upper bound on the information leakage depends solely on the fidelity between the states of the adversary. We find the lower bound for fidelity between THA states in both the polarization- and phase-coding BB84 protocols, considering both pure and mixed states. Our bounds depend only on the mean photon number per pulse available to an adversary. We also present an experimental analysis of a QKD system, including optical time-domain reflectometry measurements with centimeter resolution and spectral transmittance measurements for optical defense elements ranging from 1100 to 1800 nm with a noise floor lower than <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo>−</mo><mn>100</mn></math> dB. Finally, by considering the optimal attack, we obtain the value of the mean photon number per pulse available to an adversary and calculate the key leakage that needs to be eliminated during the privacy amplification procedure.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"31 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185204","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 : 2024-09-12DOI: 10.1103/physrevapplied.22.034034
Bhawna Sahni, Aftab Alam
Double half-Heusler (HH) alloys are a new class of compounds that can be seen as transmuted versions of two single half-Heusler alloys with higher flexibility of tunability of their properties. Here, we report a detailed study of the thermoelectric (TE) properties of two double HH alloys ( = , ), using first-principles calculation. These alloys exhibit a rich phase diagram with the possibility of tetragonal, cubic, and solid-solution phases. As such, a comparative study of the TE properties of all these phases is highly desired. The simulated band gap, obtained using a hybrid functional, of the ordered phase of and lies in the range 0.24–0.4 and 0.17–0.59 eV, respectively, while, for the disordered phase, it lies in between 0.05 and 0.06 eV. A simulated TE figure of merit () as high as 2.02 and 2.45 is obtained for and , respectively. In both compounds, electronic transport plays the dominant role in achieving the promising values. We believe this study will attract the attention not only of experimentalists but also of theoreticians from the thermoelectric community to further investigate similar double HH alloys.
{"title":"Double half-Heusler alloys X2Ni2InSb (X = Zr, Hf) with promising thermoelectric performance: The role of varying structural phases","authors":"Bhawna Sahni, Aftab Alam","doi":"10.1103/physrevapplied.22.034034","DOIUrl":"https://doi.org/10.1103/physrevapplied.22.034034","url":null,"abstract":"Double half-Heusler (HH) alloys are a new class of compounds that can be seen as transmuted versions of two single half-Heusler alloys with higher flexibility of tunability of their properties. Here, we report a detailed study of the thermoelectric (TE) properties of two double HH alloys <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>X</mi><mn>2</mn></msub><msub><mi>Ni</mi><mn>2</mn></msub><mi>InSb</mi></math> (<math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>X</mi></math> = <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Hf</mi></math>, <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Zr</mi></math>), using first-principles calculation. These alloys exhibit a rich phase diagram with the possibility of tetragonal, cubic, and solid-solution phases. As such, a comparative study of the TE properties of all these phases is highly desired. The simulated band gap, obtained using a hybrid functional, of the ordered phase of <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>Hf</mi><mn>2</mn></msub><msub><mi>Ni</mi><mn>2</mn></msub><mi>InSb</mi></math> and <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>Zr</mi><mn>2</mn></msub><msub><mi>Ni</mi><mn>2</mn></msub><mi>InSb</mi></math> lies in the range 0.24–0.4 and 0.17–0.59 eV, respectively, while, for the disordered phase, it lies in between 0.05 and 0.06 eV. A simulated TE figure of merit (<math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Z</mi><mi>T</mi></math>) as high as 2.02 and 2.45 is obtained for <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>Hf</mi><mn>2</mn></msub><msub><mi>Ni</mi><mn>2</mn></msub><mi>InSb</mi></math> and <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>Zr</mi><mn>2</mn></msub><msub><mi>Ni</mi><mn>2</mn></msub><mi>InSb</mi></math>, respectively. In both compounds, electronic transport plays the dominant role in achieving the promising <math display=\"inline\" overflow=\"scroll\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Z</mi><mi>T</mi></math> values. We believe this study will attract the attention not only of experimentalists but also of theoreticians from the thermoelectric community to further investigate similar double HH alloys.","PeriodicalId":20109,"journal":{"name":"Physical Review Applied","volume":"71 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185327","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}
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