物理与天体物理最新文献

Energy-Limited Quantum Dynamics 能量有限的量子动力学

IF 2.2 1区物理与天体物理

Communications in Mathematical Physics Pub Date : 2025-05-05 DOI: 10.1007/s00220-025-05282-w

Lauritz van Luijk

引用次数: 0

Chaotic Dynamics in Spin Torque Nano-oscillator Driven by Voltage Feedback 电压反馈驱动自旋力矩纳米振荡器的混沌动力学

IF 1.6 4区物理与天体物理

Journal of Superconductivity and Novel Magnetism Pub Date : 2025-05-05 DOI: 10.1007/s10948-025-06980-1

Meenakshi Sravani, Swapnil Bhuktare

{"title":"Chaotic Dynamics in Spin Torque Nano-oscillator Driven by Voltage Feedback","authors":"Meenakshi Sravani, Swapnil Bhuktare","doi":"10.1007/s10948-025-06980-1","DOIUrl":"10.1007/s10948-025-06980-1","url":null,"abstract":"<div><p>Non-linear dynamics, including auto-oscillations, chaotic dynamics, and synchronization, are integral to physical and biological applications and can be excited in spintronic devices. In this study, we are interested in exploring the excitation of chaos using voltage feedback in a spin torque nano-oscillator using a Magnetic Tunnel Junction (MTJ). According to the Poincaré-Bendixson theorem, chaos cannot arise in a two-dimensional system of MTJ featuring two dynamic variables describing the zenith and azimuth angles of magnetization. Hence, we prefer the feedback system as it creates a multi-dimensional system, making it interesting to explore the emergence of chaos in such systems. Such feedback is achieved by utilizing a 3-terminal device consisting of an MTJ with an in-plane pinned layer (PL) and an out-of-plane free layer (FL) geometry. When a DC current above the critical threshold is applied, the FL’s oscillating magnetization generates an AC output voltage through the Tunnel Magneto Resistance (TMR) effect. A fraction of this voltage, fed back after a delay, modulates the FL’s anisotropy via voltage controlled magnetic anisotropy (VCMA) effect, potentially driving chaotic dynamics or oscillator death based on the feedback delay and gain of the feedback circuit. The observed chaotic regime has been studied by evaluating the Lyapunov exponent, bifurcation diagrams, Fourier spectral analysis, and reconstruction of the trajectory in embedding phase space. Such observed chaotic dynamics can find practical applications in random number generators and physical reservoir computing.</p></div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"38 3","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

引用次数: 0

Ultrafast Photonic PCR with All-Solution-Processed Ti3C2Tx-Based Perfect Absorbers (Laser Photonics Rev. 19(9)/2025) 基于全溶液处理ti3c2tx完美吸收剂的超快光子PCR（激光光子学Rev. 19(9)/2025）

IF 9.8 1区物理与天体物理

Laser & Photonics Reviews Pub Date : 2025-05-05 DOI: 10.1002/lpor.202570033

Seho Lee, Abdulrahman Alsaadi, Tufail Hassan, Kyungwha Chung, Seongryeong Kim, Aleksandr Barulin, Gyoujin Cho, Chong Min Koo, Inki Kim

引用次数: 0

Issue Information: Laser & Photon. Rev. 19(9)/2025 发行信息：Laser & Photon。启19 (9)/ 2025

IF 9.8 1区物理与天体物理

Laser & Photonics Reviews Pub Date : 2025-05-05 DOI: 10.1002/lpor.202570036

引用次数: 0

Performance of the scintillation wall in the BM@N experiment 闪烁壁在BM@N实验中的性能

IF 1.5 3区物理与天体物理

Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment Pub Date : 2025-05-05 DOI: 10.1016/j.nima.2025.170529

V. Volkov , M. Golubeva , F. Guber , A. Izvestnyy , N. Karpushkin , M. Mamaev , A. Makhnev , S. Morozov , P. Parfenov

引用次数: 0

Atemporality from Conservation Laws of Physics in Lorentzian-Euclidean Black Holes 从洛伦兹-欧几里得黑洞的物理守恒定律看非时间性

IF 1.2 3区物理与天体物理

Foundations of Physics Pub Date : 2025-05-05 DOI: 10.1007/s10701-025-00848-z

Silvia De Bianchi, Salvatore Capozziello, Emmanuele Battista

引用次数: 0

Improved Bayesian regularization of inverse problems in vibrations and acoustics using noise-only measurements 改进贝叶斯正则化反问题的振动和声学使用噪声测量

IF 3.4 2区物理与天体物理

Applied Acoustics Pub Date : 2025-05-05 DOI: 10.1016/j.apacoust.2025.110756

Keaton Coletti , R. Benjamin Davis , Ryan Schultz

{"title":"Improved Bayesian regularization of inverse problems in vibrations and acoustics using noise-only measurements","authors":"Keaton Coletti , R. Benjamin Davis , Ryan Schultz","doi":"10.1016/j.apacoust.2025.110756","DOIUrl":"10.1016/j.apacoust.2025.110756","url":null,"abstract":"<div><div>This paper studies Tikhonov regularization (ridge regression) parameter selection for problems in vibrations and acoustics. The selection method is based on a popular Bayesian method, but it incorporates measurements of sensor noise. The regularization parameter is closely related to the ratio of system input energy to noise energy, so noise measurements inform the inference procedure and improve parameter identification. In cases where standard Bayesian regularization identifies zero as the optimal regularization parameter, noise measurements guarantee a unique nonzero optimum. Sufficient theoretical criteria are developed for this guarantee. The method is verified in even-determined and under-determined configurations in an acoustic source localization simulation and a vibration load identification experiment. It is shown to yield significant improvements over existing empirical Bayesian regularization. Improvements are larger in the even-determined case and smaller in the under-determined case, wherein the inverse solution is less sensitive to the regularization parameter.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"238 ","pages":"Article 110756"},"PeriodicalIF":3.4,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143903400","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}

引用次数: 0

Study of spin pumping damping and THz emission in CoFe/TixW1−x bilayers with various Ti concentrations 不同Ti浓度的CoFe/TixW1−x双分子层的自旋抽运阻尼和太赫兹发射研究

IF 4 2区物理与天体物理

Applied Physics Letters Pub Date : 2025-05-05 DOI: 10.1063/5.0252987

Zhiyao Jiang, Yuqing Zou, Ziyang Li, Yiwen Song, Jingying Zhang, Jiali Zhang, Qingyuan Jin, Zongzhi Zhang

{"title":"Study of spin pumping damping and THz emission in CoFe/TixW1−x bilayers with various Ti concentrations","authors":"Zhiyao Jiang, Yuqing Zou, Ziyang Li, Yiwen Song, Jingying Zhang, Jiali Zhang, Qingyuan Jin, Zongzhi Zhang","doi":"10.1063/5.0252987","DOIUrl":"https://doi.org/10.1063/5.0252987","url":null,"abstract":"Laser-induced magnetization dynamics and terahertz (THz) emission in CoFe/TixW1−x bilayers with varying Ti concentrations are systematically investigated using the time-resolved magneto-optical Kerr effect and time-domain THz emission spectroscopy. The incorporation of Ti into heavy metal W leads to a significant reduction in spin pumping damping, particularly for Ti concentrations below 50%. Similarly, the THz emission peak amplitude decreases with increasing Ti concentration. Both effects are attributed primarily to the reduced spin current transmittance at the CoFe/TixW1−x interface, caused by the substantially decreased electrical conductivity of the TixW1−x layer. Interestingly, while spin pumping damping continues to decrease, the THz emission amplitude starts to increase at x = 63%, where the THz signal approaches zero due to the opposite spin Hall angles of W and Ti. This behavior underscores the distinct yet correlated mechanisms governing spin pumping damping and THz emission, reflecting their specific dependences on spin current reflection, propagation, dissipation, and spin-to-charge conversion in ferromagnet/nonmagnetic metal bilayer systems. These findings enhance our understanding of ultrafast spin dynamics and spin transport properties, offering valuable insights for advancing the development of miniaturized and high-speed spintronic devices.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"2 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143905755","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}

引用次数: 0

High-Performance Chiral Mode Switching Devices Using Silicon Metamaterial Waveguides Beyond 1.55 µm (Laser Photonics Rev. 19(9)/2025) 基于1.55µm以上硅超材料波导的高性能手性模式开关器件（激光光子学Rev. 19(9)/2025）

IF 9.8 1区物理与天体物理

Laser & Photonics Reviews Pub Date : 2025-05-05 DOI: 10.1002/lpor.202570035

Kang Li, Hejie Peng, Siwei Wang, Qiyuan Yi, Lin Chen, Yu Zhang, Jinwei Zeng, Jian Wang

引用次数: 0

The sound radiated by tip clearances submerged in a boundary layer 淹没在边界层中的尖端间隙所辐射的声音

IF 3.4 2区物理与天体物理

Applied Acoustics Pub Date : 2025-05-05 DOI: 10.1016/j.apacoust.2025.110741

Manuj Awasthi , Danielle Moreau , Paul Croaker , Paul Dylejko

{"title":"The sound radiated by tip clearances submerged in a boundary layer","authors":"Manuj Awasthi , Danielle Moreau , Paul Croaker , Paul Dylejko","doi":"10.1016/j.apacoust.2025.110741","DOIUrl":"10.1016/j.apacoust.2025.110741","url":null,"abstract":"<div><div>The present study investigates the behaviour of the far-field sound radiated by low Mach number tip clearance flow induced by placing a stationary cambered airfoil adjacent to a stationary wall. The tip clearance heights ranged from 14% to 30% of the incoming, undisturbed boundary layer thickness and the clearance heights based Reynolds numbers were between 2,600 and 16,000. The far-field sound measured using a microphone array was beamformed to reveal the dominant noise sources and how they behave when the flow Mach number, angle of attack and the clearance height were varied. The near-field behaviour was also examined through PIV measurements and surface pressure fluctuation measurements on the tip. The results show that the mid-to-high frequency noise generated by tip clearances is dominated by the leakage flow in the mid-chord and leading-edge regions, while a distinct low-frequency noise source with a different scaling behaviour exists close to the trailing-edge of the tip clearance. The origin of this low-frequency noise source is believed to be the tip separation vortex that resides close to the trailing-edge and induces significant turbulence levels in the region. The strength of this noise source decreases with clearance height which is consistent with a reduction in turbulence levels associated with the separation vortex. The magnitude of the mid-frequency clearance noise which scales with the sixth power of the Mach number, decreases with tip clearance height due to a reduction in the fluctuating pressure on the airfoil tip surface. The time-scale of this sound was independent of the flow velocity, implying that the source is non-compact. Smaller tip clearances were also found to generate louder high-frequency noise due to intense turbulence and pressure fluctuation levels concentrated near the leading-edge of the clearance.</div></div>","PeriodicalId":55506,"journal":{"name":"Applied Acoustics","volume":"238 ","pages":"Article 110741"},"PeriodicalIF":3.4,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143903398","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}

引用次数: 0