Pub Date : 2024-09-19DOI: 10.1103/physreva.110.032817
Denis Mishin, Dmitry Tregubov, Nikolay Kolachevsky, Artem Golovizin
We present refined values of the hyperfine splitting frequencies of the ground and clock states of thulium atoms, Hz and Hz, respectively. The measurements are performed on an ultracold atomic ensemble in an optical lattice using combined microwave and optical transition spectroscopy. The achieved measurement accuracy of less than 0.1 ppb represents an improvement of 2 and 7 orders of magnitude for and , respectively, compared to the previously published values. We also refine the value of the Landé -factor of the clock level to . The results of this work can be used in the frequency standards and quantum simulators based on thulium atoms being developed today, as well as in a number of fundamental studies that require precise knowledge of the hyperfine structure characteristics of various elements.
{"title":"Combined microwave and optical spectroscopy for hyperfine structure analysis in thulium atoms","authors":"Denis Mishin, Dmitry Tregubov, Nikolay Kolachevsky, Artem Golovizin","doi":"10.1103/physreva.110.032817","DOIUrl":"https://doi.org/10.1103/physreva.110.032817","url":null,"abstract":"We present refined values of the hyperfine splitting frequencies of the ground <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mrow><mo>|</mo><mi>g</mi><mo>〉</mo></mrow><mo>=</mo><mrow><mrow><mo>|</mo></mrow><mrow><mn>4</mn><msup><mi>f</mi><mn>13</mn></msup><mrow><msup><mo>(</mo><mn>2</mn></msup><msup><mi>F</mi><mi>o</mi></msup><mo>)</mo></mrow><mn>6</mn><msup><mi>s</mi><mn>2</mn></msup><mo>,</mo><mi>J</mi><mo>=</mo><mn>7</mn><mo>/</mo><mn>2</mn></mrow><mrow><mo>〉</mo></mrow></mrow></mrow></math> and clock <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mrow><mo>|</mo><mi>c</mi><mo>〉</mo></mrow><mo>=</mo><mrow><mrow><mo>|</mo></mrow><mrow><mn>4</mn><msup><mi>f</mi><mn>13</mn></msup><mrow><msup><mo>(</mo><mn>2</mn></msup><msup><mi>F</mi><mi>o</mi></msup><mo>)</mo></mrow><mn>6</mn><msup><mi>s</mi><mn>2</mn></msup><mo>,</mo><mi>J</mi><mo>=</mo><mn>5</mn><mo>/</mo><mn>2</mn></mrow><mrow><mo>〉</mo></mrow></mrow></mrow></math> states of thulium atoms, <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msubsup><mi>f</mi><mrow><mi>g</mi></mrow><mtext>HFS</mtext></msubsup><mo>=</mo><mn>1</mn><mspace width=\"0.16em\"></mspace><mn>496</mn><mspace width=\"0.16em\"></mspace><mn>550</mn><mspace width=\"0.16em\"></mspace><mn>658.23</mn><mrow><mo>(</mo><mn>3</mn><mo>)</mo></mrow></mrow></math> Hz and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msubsup><mi>f</mi><mrow><mi>c</mi></mrow><mtext>HFS</mtext></msubsup><mo>=</mo><mn>2</mn><mspace width=\"0.16em\"></mspace><mn>113</mn><mspace width=\"0.16em\"></mspace><mn>946</mn><mspace width=\"0.16em\"></mspace><mn>873.08</mn><mrow><mo>(</mo><mn>9</mn><mo>)</mo></mrow></mrow></math> Hz, respectively. The measurements are performed on an ultracold atomic ensemble in an optical lattice using combined microwave and optical transition spectroscopy. The achieved measurement accuracy of less than 0.1 ppb represents an improvement of 2 and 7 orders of magnitude for <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msubsup><mi>f</mi><mrow><mi>g</mi></mrow><mtext>HFS</mtext></msubsup></math> and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msubsup><mi>f</mi><mrow><mi>c</mi></mrow><mtext>HFS</mtext></msubsup></math>, respectively, compared to the previously published values. We also refine the value of the Landé <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>g</mi></math>-factor of the clock level to <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>g</mi><mi>c</mi></msub><mo>=</mo><mn>0.854</mn><mspace width=\"0.16em\"></mspace><mn>786</mn><mrow><mo>(</mo><mn>12</mn><mo>)</mo></mrow></mrow></math>. The results of this work can be used in the frequency standards and quantum simulators based on thulium atoms being developed today, as well as in a number of fundamental studies that require precise knowledge of the hyperfine structure characteristics of various elements.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"4 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262764","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 : 2024-09-19DOI: 10.1103/physreva.110.033112
Dilfuza Umarova, Otabek Umarov, Attila Tóth, András Csehi
We study by real-time wave-packet simulations the sequential two-photon dissociation of the molecule, under intense ultraviolet laser pulses of narrow spectral width. By a resonant coupling, one-photon Rabi oscillations are generated between two vibrational levels of the molecule, belonging to two different bound electronic states. These vibronic Rabi oscillations are probed upon absorption of further photons from the same laser pulse, that gradually promote the molecule to a dissociative electronic state. Calculating the energy spectrum of the photofragments explicitly analytically, we elucidate the physical origin of the main spectral features—such as the splitting, shifting, asymmetry, and multipeak pattern—identified by accurate numerical simulations. We find that the pronounced spectral intensity modulations result from the interference of fragment amplitudes that are generated during the distinct Rabi cycles in the upper and lower dynamically dressed states, formed upon the resonant coupling with the laser pulse. These intensity modulations are sensitively influenced by the resonant and nonresonant Stark effects, and can be manipulated by the parameters of the applied laser pulse. Our results contribute to the understanding and control of ultrafast coherent phenomena via the energy spectrum of particles emitted during the dynamical process under investigation.
{"title":"Spectral evidence of vibronic Rabi oscillations in the resonance-enhanced photodissociation of MgH+","authors":"Dilfuza Umarova, Otabek Umarov, Attila Tóth, András Csehi","doi":"10.1103/physreva.110.033112","DOIUrl":"https://doi.org/10.1103/physreva.110.033112","url":null,"abstract":"We study by real-time wave-packet simulations the sequential two-photon dissociation of the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mrow><mi>MgH</mi></mrow><mo>+</mo></msup></math> molecule, under intense ultraviolet laser pulses of narrow spectral width. By a resonant coupling, one-photon Rabi oscillations are generated between two vibrational levels of the molecule, belonging to two different bound electronic states. These vibronic Rabi oscillations are probed upon absorption of further photons from the same laser pulse, that gradually promote the molecule to a dissociative electronic state. Calculating the energy spectrum of the photofragments explicitly analytically, we elucidate the physical origin of the main spectral features—such as the splitting, shifting, asymmetry, and multipeak pattern—identified by accurate numerical simulations. We find that the pronounced spectral intensity modulations result from the interference of fragment amplitudes that are generated during the distinct Rabi cycles in the upper and lower dynamically dressed states, formed upon the resonant coupling with the laser pulse. These intensity modulations are sensitively influenced by the resonant and nonresonant Stark effects, and can be manipulated by the parameters of the applied laser pulse. Our results contribute to the understanding and control of ultrafast coherent phenomena via the energy spectrum of particles emitted during the dynamical process under investigation.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"27 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262765","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 : 2024-09-19DOI: 10.1103/physreva.110.032816
Gregory S. Adkins, Ulrich D. Jentschura
For an accurate theoretical description of muonic bound systems, it is crucial to consistently treat relativistic and recoil corrections to vacuum polarization. The one-loop vacuum-polarization effect is by far the dominant quantum electrodynamic (QED) energy correction for bound muons, being of order , where is the fine-structure constant, is the nuclear charge number, and is the reduced mass. Gauge invariance of the relativistic and recoil corrections to vacuum polarization of order is investigated with respect to nonretarded and standard, renormalized variants of Coulomb gauge. The invariance is shown after including three-photon exchange diagrams. Our derivation is based on an adapted form of nonrelativistic quantum electrodynamics for bound muon systems (), which is a version of NRQED where the hard scale is set at the muon mass instead of the electron mass. Updated values for the gauge-independent corrections for one-muon ions with nuclear charge numbers are presented.
{"title":"Relativistic and recoil corrections to vacuum polarization in muonic systems: Three-photon exchange, gauge invariance, and numerical values","authors":"Gregory S. Adkins, Ulrich D. Jentschura","doi":"10.1103/physreva.110.032816","DOIUrl":"https://doi.org/10.1103/physreva.110.032816","url":null,"abstract":"For an accurate theoretical description of muonic bound systems, it is crucial to consistently treat relativistic and recoil corrections to vacuum polarization. The one-loop vacuum-polarization effect is by far the dominant quantum electrodynamic (QED) energy correction for bound muons, being of order <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>α</mi><msup><mrow><mo>(</mo><mi>Z</mi><mi>α</mi><mo>)</mo></mrow><mn>2</mn></msup><msub><mi>m</mi><mi>r</mi></msub></mrow></math>, where <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>α</mi></math> is the fine-structure constant, <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>Z</mi></math> is the nuclear charge number, and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>m</mi><mi>r</mi></msub></math> is the reduced mass. Gauge invariance of the relativistic and recoil corrections to vacuum polarization of order <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>α</mi><msup><mrow><mo>(</mo><mi>Z</mi><mi>α</mi><mo>)</mo></mrow><mn>4</mn></msup><msub><mi>m</mi><mi>r</mi></msub></mrow></math> is investigated with respect to nonretarded and standard, renormalized variants of Coulomb gauge. The invariance is shown after including three-photon exchange diagrams. Our derivation is based on an adapted form of nonrelativistic quantum electrodynamics for bound muon systems (<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>NRQED</mi><mi>μ</mi></msub></math>), which is a version of NRQED where the hard scale is set at the muon mass instead of the electron mass. Updated values for the gauge-independent corrections for one-muon ions with nuclear charge numbers <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>Z</mi><mo>=</mo><mn>1</mn><mo>,</mo><mn>2</mn><mo>,</mo><mn>6</mn></mrow></math> are presented.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"24 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262762","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 : 2024-09-19DOI: 10.1103/physreva.110.033321
Alice Marché, Hironobu Yoshida, Alberto Nardin, Hosho Katsura, Leonardo Mazza
We study the late-time dynamics of two particles confined in one spatial dimension and subject to two-body losses. The dynamics is exactly described by a non-Hermitian Hamiltonian that can be analytically studied both in the continuum and on a lattice. The asymptotic decay rate and the universal power-law form of the decay of the number of particles are exactly computed in the whole parameter space of the problem. When in the initial state the two particles are far apart, the average number of particles in the setup decays with time as ; a different power law, , is found when the two particles overlap in the initial state. These results are valid both in the continuum and on a lattice, but in the latter case a logarithmic correction appears.
我们研究了限制在一个空间维度并受到双体损耗的两个粒子的晚期动力学。该动力学由非赫米特哈密顿精确描述，可在连续体和晶格上进行分析研究。在问题的整个参数空间中，粒子数量的渐进衰减率和衰减的普遍幂律形式都是精确计算出来的。当初始状态中的两个粒子相距甚远时，设置中粒子的平均数量随时间 t 的衰减为 t-1/2；当初始状态中的两个粒子重叠时，发现了不同的幂律，即 t-3/2。这些结果在连续体和晶格上都有效，但在后一种情况下会出现对数修正。
{"title":"Universality and two-body losses: Lessons from the effective non-Hermitian dynamics of two particles","authors":"Alice Marché, Hironobu Yoshida, Alberto Nardin, Hosho Katsura, Leonardo Mazza","doi":"10.1103/physreva.110.033321","DOIUrl":"https://doi.org/10.1103/physreva.110.033321","url":null,"abstract":"We study the late-time dynamics of two particles confined in one spatial dimension and subject to two-body losses. The dynamics is exactly described by a non-Hermitian Hamiltonian that can be analytically studied both in the continuum and on a lattice. The asymptotic decay rate and the universal power-law form of the decay of the number of particles are exactly computed in the whole parameter space of the problem. When in the initial state the two particles are far apart, the average number of particles in the setup decays with time <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>t</mi></math> as <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mi>t</mi><mrow><mo>−</mo><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup></math>; a different power law, <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mi>t</mi><mrow><mo>−</mo><mn>3</mn><mo>/</mo><mn>2</mn></mrow></msup></math>, is found when the two particles overlap in the initial state. These results are valid both in the continuum and on a lattice, but in the latter case a logarithmic correction appears.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"30 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262766","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 : 2024-09-18DOI: 10.1103/physreva.110.032617
Julia A. Kunzelmann, Hermann Kampermann, Dagmar Bruß
This work explores the important role of quantum routers in communication networks and investigates the increase in efficiency using memories and multiplexing strategies. Motivated by the bipartite setup introduced by Abruzzo et al. [Phys. Rev. A89, 012303 (2014)] for finite-range multiplexing in quantum repeaters, we extend the study to an -partite network with a router as a central station. We present a general protocol for parties after defining the underlying matching problem and we calculate the router rate for different . We analyze the improvement due to multiplexing and analyze the secret key rate with explicit results for the tripartite network. Investigating strategic qubit selection for the Greenberger-Horne-Zeilinger measurements, we show that using cutoffs to remove qubits after a certain number of rounds and consistently combining qubits with the lowest number of storage rounds leads to an optimal secret key rate.
这项研究探讨了量子路由器在通信网络中的重要作用，并研究了利用存储器和复用策略提高效率的问题。受 Abruzzo 等人[Phys. Rev. A 89, 012303 (2014)]介绍的量子中继器中有限范围复用的两方设置的启发，我们将研究扩展到以路由器为中心站的 N 方网络。在定义了底层匹配问题之后，我们提出了一个适用于 N 方的通用协议，并计算了不同 N 的路由器速率。我们分析了多路复用带来的改进，并用三方网络的明确结果分析了秘钥速率。在研究格林伯格-霍恩-蔡林格测量的策略性量子比特选择时，我们表明，在一定轮数后使用截止来移除量子比特，并持续组合存储轮数最少的量子比特，可以获得最佳秘钥率。
{"title":"Multipartite multiplexing strategies for quantum routers","authors":"Julia A. Kunzelmann, Hermann Kampermann, Dagmar Bruß","doi":"10.1103/physreva.110.032617","DOIUrl":"https://doi.org/10.1103/physreva.110.032617","url":null,"abstract":"This work explores the important role of quantum routers in communication networks and investigates the increase in efficiency using memories and multiplexing strategies. Motivated by the bipartite setup introduced by Abruzzo <i>et al.</i> [<span>Phys. Rev. A</span> <b>89</b>, 012303 (2014)] for finite-range multiplexing in quantum repeaters, we extend the study to an <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>N</mi></math>-partite network with a router as a central station. We present a general protocol for <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>N</mi></math> parties after defining the underlying matching problem and we calculate the router rate for different <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>N</mi></math>. We analyze the improvement due to multiplexing and analyze the secret key rate with explicit results for the tripartite network. Investigating strategic qubit selection for the Greenberger-Horne-Zeilinger measurements, we show that using cutoffs to remove qubits after a certain number of rounds and consistently combining qubits with the lowest number of storage rounds leads to an optimal secret key rate.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"31 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262773","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 : 2024-09-18DOI: 10.1103/physreva.110.032616
E. A. Vashukevich, T. Yu. Golubeva
The paper presents an analysis of entangling and nonlocal operations in a quantum nondemolition (QND) interaction between multimode light with orbital angular momentum and an atomic ensemble. A protocol consists of two QND operations with rotations of quadratures of atomic spin coherence and light between them. This protocol provides a wide range of two-qubit operations, while the multimode nature of the chosen degrees of freedom allows the implementation of parallel operations over multiple two-qubit systems. We have used the formalism of equivalence classes and local invariants to evaluate the properties of two-qubit transformations. It is shown that, when selecting suitable values of the governing parameters, such as the duration of each of the two QND interactions and the rotation angles of the qubits, the protocol allows to realize a deterministic nonlocal SWAP operation and entangling operation with probability .
{"title":"Parallel two-qubit entangling gates via a quantum nondemolition interaction controlled by rotation","authors":"E. A. Vashukevich, T. Yu. Golubeva","doi":"10.1103/physreva.110.032616","DOIUrl":"https://doi.org/10.1103/physreva.110.032616","url":null,"abstract":"The paper presents an analysis of entangling and nonlocal operations in a quantum nondemolition (QND) interaction between multimode light with orbital angular momentum and an atomic ensemble. A protocol consists of two QND operations with rotations of quadratures of atomic spin coherence and light between them. This protocol provides a wide range of two-qubit operations, while the multimode nature of the chosen degrees of freedom allows the implementation of parallel operations over multiple two-qubit systems. We have used the formalism of equivalence classes and local invariants to evaluate the properties of two-qubit transformations. It is shown that, when selecting suitable values of the governing parameters, such as the duration of each of the two QND interactions and the rotation angles of the qubits, the protocol allows to realize a deterministic nonlocal SWAP operation and entangling <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msqrt><mtext>SWAP</mtext></msqrt></math> operation with probability <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mfrac><mn>1</mn><mn>3</mn></mfrac></math>.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"27 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262772","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 : 2024-09-18DOI: 10.1103/physreva.110.032814
S. Majumdar, S. Bastola, A. Hasan, R. Lomsadze, M. Schulz
We have measured fully differential cross sections (FDCSs) for ionization of helium by 75 keV proton impact. Data were analyzed for electrons ejected into the scattering plane at projectile energy losses well below and above the matching velocity and for scattering angles ranging between 0.1 and 0.5 mrad. Earlier, we observed clear signatures of the postcollision interaction (PCI) at the matching velocity; however, in the current data these signatures are completely absent at small energy losses and residues remain at large energy losses. At small energy losses the FDCSs are dominated by non-PCI higher-order effects.
{"title":"Separation of various higher-order effects in the ionization of helium by proton impact","authors":"S. Majumdar, S. Bastola, A. Hasan, R. Lomsadze, M. Schulz","doi":"10.1103/physreva.110.032814","DOIUrl":"https://doi.org/10.1103/physreva.110.032814","url":null,"abstract":"We have measured fully differential cross sections (FDCSs) for ionization of helium by 75 keV proton impact. Data were analyzed for electrons ejected into the scattering plane at projectile energy losses well below and above the matching velocity and for scattering angles ranging between 0.1 and 0.5 mrad. Earlier, we observed clear signatures of the postcollision interaction (PCI) at the matching velocity; however, in the current data these signatures are completely absent at small energy losses and residues remain at large energy losses. At small energy losses the FDCSs are dominated by non-PCI higher-order effects.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"77 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262921","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}
The release of the causal structure of physical events from a well-defined order to an indefinite order stimulates remarkable enhancements in various quantum information tasks. Some of these advantages, however, are questioned for the ambiguous role of the control system in the quantum switch, which is an experimentally realized process with an indefinite causal structure. In communications, for example, not only the superposition of alternative causal orders, but also the superposition of alternative trajectories can accelerate information transmissions. Here, we follow the proposal of Liu et al. [Phys. Rev. Lett.129, 230604 (2022)], and examine the information enhancement effect of indefinite causal orders with the toolkit of thermodynamics in a photonic platform. Specifically, we simulate the thermal interaction between a system qubit and two heat baths embedded in a quantum switch by implementing the corresponding switched thermal channels. Although its action on the system qubit only is thermally free, our results suggest that the quantum switch should be seen as a resource when the control qubit is also considered. Moreover, we characterize the non-Markovian property in this scenario by measuring the information backflows from the heat baths to the system qubit.
物理事件的因果结构从定义明确的顺序变为不确定的顺序，激发了各种量子信息任务的显著提升。然而，由于量子开关中控制系统的作用不明确，其中一些优势受到质疑，因为量子开关是一个实验实现的过程，具有不确定的因果结构。例如，在通信中，不仅替代因果顺序的叠加，而且替代轨迹的叠加都能加速信息传输。在此，我们按照刘等人的建议[Phys. Rev. Lett. 129, 230604 (2022)]，在光子平台上利用热力学工具包研究了不定因果顺序的信息增强效应。具体来说，我们通过实现相应的开关热通道，模拟了系统量子比特与嵌入量子开关的两个热浴之间的热相互作用。虽然量子开关对系统量子比特的作用是热自由的，但我们的结果表明，当同时考虑控制量子比特时，量子开关应被视为一种资源。此外，我们还通过测量从热浴到系统量子位的信息回流，描述了这种情况下的非马尔可夫特性。
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Pub Date : 2024-09-18DOI: 10.1103/physreva.110.033520
Ozan Akdemir, Minh Duy Truong, Alfredo Rates, Ad Lagendijk, Willem L. Vos
The accurate determination of the position-dependent energy fluence rate of scattered light (which is proportional to the energy density) is crucial to the understanding of transport in anisotropically scattering and absorbing samples, such as biological tissue, seawater, atmospheric turbulent layers, and light-emitting diodes. While Monte Carlo simulations are precise, their long computation time is not desirable. Common analytical approximations to the radiative transfer equation (RTE) fail to predict light transport and could even give unphysical results. Therefore, we experimentally probe the position-dependent energy fluence rate of light inside scattering samples where the widely used and approximations to the RTE fail. The samples are three-dimensional (3D) aqueous suspensions of anisotropically scattering and both absorbing and nonabsorbing spherical scatterers, namely, microspheres () with and without absorbing dye. To probe the energy fluence rate, we detect the emission of quantum-dot reporter particles that are excited by the incident light and that are contained in a thin capillary. By scanning the capillary through the sample, we access the position dependence. We present a comprehensive discussion of experimental limitations and of both random and systematic errors. Our observations agree well with the Monte Carlo simulations and the approximation of the RTE with a correction for forward scattering. In contrast, the and the approximations deviate increasingly from our observations, ultimately even predicting unphysical negative energies.
{"title":"Probing the position-dependent optical energy fluence rate in three-dimensional scattering samples","authors":"Ozan Akdemir, Minh Duy Truong, Alfredo Rates, Ad Lagendijk, Willem L. Vos","doi":"10.1103/physreva.110.033520","DOIUrl":"https://doi.org/10.1103/physreva.110.033520","url":null,"abstract":"The accurate determination of the position-dependent energy fluence rate of scattered light (which is proportional to the energy density) is crucial to the understanding of transport in anisotropically scattering and absorbing samples, such as biological tissue, seawater, atmospheric turbulent layers, and light-emitting diodes. While Monte Carlo simulations are precise, their long computation time is not desirable. Common analytical approximations to the radiative transfer equation (RTE) fail to predict light transport and could even give unphysical results. Therefore, we experimentally probe the position-dependent energy fluence rate of light inside scattering samples where the widely used <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>P</mi><mn>1</mn></msub></math> and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>P</mi><mn>3</mn></msub></math> approximations to the RTE fail. The samples are three-dimensional (3D) aqueous suspensions of anisotropically scattering and both absorbing and nonabsorbing spherical scatterers, namely, microspheres (<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>r</mi><mo>=</mo><mn>0.5</mn><mspace width=\"3.33333pt\"></mspace><mi>µ</mi><mi mathvariant=\"normal\">m</mi></mrow></math>) with and without absorbing dye. To probe the energy fluence rate, we detect the emission of quantum-dot reporter particles that are excited by the incident light and that are contained in a thin capillary. By scanning the capillary through the sample, we access the position dependence. We present a comprehensive discussion of experimental limitations and of both random and systematic errors. Our observations agree well with the Monte Carlo simulations and the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>P</mi><mn>3</mn></msub></math> approximation of the RTE with a correction for forward scattering. In contrast, the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>P</mi><mn>1</mn></msub></math> and the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>P</mi><mn>3</mn></msub></math> approximations deviate increasingly from our observations, ultimately even predicting unphysical negative energies.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"171 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262919","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 : 2024-09-18DOI: 10.1103/physreva.110.032216
A. J. MacLeod, B. King
Direct measurement of the elastic scattering of real photons on an electromagnetic field would allow the fundamental low-energy constants of quantum electrodynamics to be experimentally determined. We show that scenarios involving the collision of three laser beams have several advantages over conventional two-beam scenarios. The kinematics of a three-beam collision allows for a higher signal-to-background ratio in the detection region, without the need for polarimetry, and separates out contributions from different orders of photon scattering. A planar configuration of colliding a photon beam from an x-ray free-electron laser with two optical beams is studied in detail. We show that measurements of elastic photon scattering and vacuum birefringence are possible with currently available technology.
直接测量真实光子在电磁场上的弹性散射，可以通过实验确定量子电动力学的基本低能常数。我们的研究表明，与传统的双光束方案相比，涉及三束激光碰撞的方案具有若干优势。三光束碰撞的运动学原理使探测区域的信噪比更高，无需偏振测量法，并能分离出不同数量级的光子散射。我们详细研究了将来自 X 射线自由电子激光器的光子束与两束光束碰撞的平面配置。我们表明，利用现有技术可以测量弹性光子散射和真空双折射。
{"title":"Fundamental constants from photon-photon scattering in three-beam collisions","authors":"A. J. MacLeod, B. King","doi":"10.1103/physreva.110.032216","DOIUrl":"https://doi.org/10.1103/physreva.110.032216","url":null,"abstract":"Direct measurement of the elastic scattering of real photons on an electromagnetic field would allow the fundamental low-energy constants of quantum electrodynamics to be experimentally determined. We show that scenarios involving the collision of three laser beams have several advantages over conventional two-beam scenarios. The kinematics of a three-beam collision allows for a higher signal-to-background ratio in the detection region, without the need for polarimetry, and separates out contributions from different orders of photon scattering. A planar configuration of colliding a photon beam from an x-ray free-electron laser with two optical beams is studied in detail. We show that measurements of elastic photon scattering and vacuum birefringence are possible with currently available technology.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"3 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262771","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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