Pub Date : 2024-09-13DOI: 10.1103/physreva.110.033106
S. Q. Shen, Z. Y. Chen, S. Wang, J. Y. Che, Y. J. Chen
We numerically and analytically study ionization of with large internuclear distances in strong elliptically polarized laser fields. Numerical simulations show that the offset angle in the photoelectron momentum distribution (PMD) is larger for cases of large than for cases of with small and model atoms with similar ionization potentials. In addition, the PMDs for cases of large show clear interference patterns which disappear for cases of small . By developing a strong-field model which includes the contributions of the first excited state and the Coulomb potential, we reproduce the phenomena for large . Tunneling ionization of with large involves a complex four-body interaction between the laser, the electron, and the two nuclei. Our model can approximate the four-body interaction as the three-body one and clearly identify the effects of charge resonance and different nuclei on tunneling ionization. Our work suggests a manner for probing complex interactions in strong-field ionization of stretched molecules with high time resolution.
我们通过数值和分析研究了核间距 R 较大的 H2+ 在强椭圆偏振激光场中的电离情况。数值模拟结果表明，与具有类似电离势的小 R H2+和模型原子相比，大 R 情况下光电子动量分布（PMD）的偏移角更大。通过建立一个包括第一激发态和库仑势贡献的强场模型，我们再现了大 R 的现象。大 R H2+ 的隧道电离涉及激光、电子和两个原子核之间复杂的四体相互作用。我们的模型可以将四体相互作用近似为三体相互作用，并清晰地识别出电荷共振和不同原子核对隧道电离的影响。我们的工作提出了一种以高时间分辨率探测拉伸分子强场电离中复杂相互作用的方法。
{"title":"Coulomb effects on strong-field ionization of stretched H2+","authors":"S. Q. Shen, Z. Y. Chen, S. Wang, J. Y. Che, Y. J. Chen","doi":"10.1103/physreva.110.033106","DOIUrl":"https://doi.org/10.1103/physreva.110.033106","url":null,"abstract":"We numerically and analytically study ionization of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi mathvariant=\"normal\">H</mi><mn>2</mn></msub><msup><mrow></mrow><mo>+</mo></msup></mrow></math> with large internuclear distances <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>R</mi></math> in strong elliptically polarized laser fields. Numerical simulations show that the offset angle in the photoelectron momentum distribution (PMD) is larger for cases of large <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>R</mi></math> than for cases of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi mathvariant=\"normal\">H</mi><mn>2</mn></msub><msup><mrow></mrow><mo>+</mo></msup></mrow></math> with small <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>R</mi></math> and model atoms with similar ionization potentials. In addition, the PMDs for cases of large <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>R</mi></math> show clear interference patterns which disappear for cases of small <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>R</mi></math>. By developing a strong-field model which includes the contributions of the first excited state and the Coulomb potential, we reproduce the phenomena for large <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>R</mi></math>. Tunneling ionization of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi mathvariant=\"normal\">H</mi><mn>2</mn></msub><msup><mrow></mrow><mo>+</mo></msup></mrow></math> with large <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>R</mi></math> involves a complex four-body interaction between the laser, the electron, and the two nuclei. Our model can approximate the four-body interaction as the three-body one and clearly identify the effects of charge resonance and different nuclei on tunneling ionization. Our work suggests a manner for probing complex interactions in strong-field ionization of stretched molecules with high time resolution.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"57 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205854","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/physreva.110.032417
Bing Xu, Xiaofei Qi, Jinchuan Hou
We discuss the behavior of positive linear maps in fermionic systems and then propose the phase partial transpose and the phase entanglement negativity. We show that every fermionic state which mixes local fermion-number parity must have nonvanishing nontrivial phase entanglement negativity, which gives an affirmative answer to a conjecture proposed by Shapourian and Ryu [Phys. Rev. A99, 022310 (2019)]. In addition, we prove that the phase entanglement negativity is an entanglement monotone and establish some equalities and inequalities related to the phase entanglement negativity which, particularly, provide some upper bounds and lower bounds of the fermionic entanglement negativity. A more detailed discussion of the -mode case is also presented, and our results generalize some known findings.
{"title":"Phase entanglement negativity for bipartite fermionic systems","authors":"Bing Xu, Xiaofei Qi, Jinchuan Hou","doi":"10.1103/physreva.110.032417","DOIUrl":"https://doi.org/10.1103/physreva.110.032417","url":null,"abstract":"We discuss the behavior of positive linear maps in fermionic systems and then propose the phase partial transpose and the phase entanglement negativity. We show that every fermionic state which mixes local fermion-number parity must have nonvanishing nontrivial phase entanglement negativity, which gives an affirmative answer to a conjecture proposed by Shapourian and Ryu [<span>Phys. Rev. A</span> <b>99</b>, 022310 (2019)]. In addition, we prove that the phase entanglement negativity is an entanglement monotone and establish some equalities and inequalities related to the phase entanglement negativity which, particularly, provide some upper bounds and lower bounds of the fermionic entanglement negativity. A more detailed discussion of the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mo>(</mo><mn>1</mn><mo>+</mo><mi>M</mi><mo>)</mo></mrow></math>-mode case is also presented, and our results generalize some known findings.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"61 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205848","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/physreva.110.032613
Nicolò Lo Piparo, William J. Munro, Kae Nemoto
Advanced quantum networking systems rely on efficient quantum error correction codes for their optimal realization. The rate at which the encoded information is transmitted is a fundamental limit that affects the performance of such systems. Quantum aggregation allows one to increase the transmission rate by adding multiple paths connecting two distant users. Aggregating channels of different paths allows more users to simultaneously exchange the encoded information. Recent work has shown that quantum aggregation can also reduce the number of physical resources of an error correction code when it is combined with the quantum multiplexing technique. However, the difference in channel lengths across the various paths means some of the encoded quantum information will arrive earlier than others and it must be stored in quantum memories. The information stored will then deteriorate due to decoherence processes leading to detrimental effects for the fidelity of the final quantum state. Here, we explore the effects of a depolarization channel that occurs for the quantum Reed-Solomon code when quantum aggregation involving different channel lengths is used. We determine the best distribution of resources among the various channels connecting two remote users. Furthermore, we estimate the coherence time required to achieve a certain fidelity. Our results will have a significant impact on the ways physical resources are distributed across a quantum network.
{"title":"Quantum aggregation with temporal delay","authors":"Nicolò Lo Piparo, William J. Munro, Kae Nemoto","doi":"10.1103/physreva.110.032613","DOIUrl":"https://doi.org/10.1103/physreva.110.032613","url":null,"abstract":"Advanced quantum networking systems rely on efficient quantum error correction codes for their optimal realization. The rate at which the encoded information is transmitted is a fundamental limit that affects the performance of such systems. Quantum aggregation allows one to increase the transmission rate by adding multiple paths connecting two distant users. Aggregating channels of different paths allows more users to simultaneously exchange the encoded information. Recent work has shown that quantum aggregation can also reduce the number of physical resources of an error correction code when it is combined with the quantum multiplexing technique. However, the difference in channel lengths across the various paths means some of the encoded quantum information will arrive earlier than others and it must be stored in quantum memories. The information stored will then deteriorate due to decoherence processes leading to detrimental effects for the fidelity of the final quantum state. Here, we explore the effects of a depolarization channel that occurs for the quantum Reed-Solomon code when quantum aggregation involving different channel lengths is used. We determine the best distribution of resources among the various channels connecting two remote users. Furthermore, we estimate the coherence time required to achieve a certain fidelity. Our results will have a significant impact on the ways physical resources are distributed across a quantum network.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"49 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205849","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/physreva.110.032418
Rongfeng Xie, Alex Kamenev
We discuss adiabatic spectra and dynamics of the quantum, i.e., transverse field, Hopfield model with dilute memories (the number of stored patterns, , where is the number of qubits). At some critical transverse field, the model undergoes the quantum phase transition from the ordered to the paramagnetic state. The corresponding critical exponents are calculated and used to determine the efficiency of quantum annealing protocols. We also discuss implications of these results for the quantum annealing of generic spin glass models.
我们讨论了具有稀释记忆（存储模式的数量，p<log2N，其中 N 是量子比特的数量）的量子（即横向场）Hopfield 模型的绝热光谱和动力学。在某个临界横向场下，模型会发生从有序态到顺磁态的量子相变。我们计算了相应的临界指数，并用它来确定量子退火协议的效率。我们还讨论了这些结果对一般自旋玻璃模型量子退火的影响。
{"title":"Quantum Hopfield model with dilute memories","authors":"Rongfeng Xie, Alex Kamenev","doi":"10.1103/physreva.110.032418","DOIUrl":"https://doi.org/10.1103/physreva.110.032418","url":null,"abstract":"We discuss adiabatic spectra and dynamics of the quantum, i.e., transverse field, Hopfield model with dilute memories (the number of stored patterns, <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>p</mi><mo><</mo><msub><mo form=\"prefix\">log</mo><mn>2</mn></msub><mi>N</mi></mrow></math>, where <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>N</mi></math> is the number of qubits). At some critical transverse field, the model undergoes the quantum phase transition from the ordered to the paramagnetic state. The corresponding critical exponents are calculated and used to determine the efficiency of quantum annealing protocols. We also discuss implications of these results for the quantum annealing of generic spin glass models.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"18 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262618","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/physreva.110.033108
Andrew S. Maxwell, Lars Bojer Madsen
Spin-orbit dynamics and relativistic corrections to the kinetic energy in strong-field dynamics have long been ignored for near- and mid-infrared fields with intensities , as the final photoelectron energies are considered too low for these effects to play a role. However, using a precise and flexible path-integral formalism, we include all correction terms from the fine-structure, Breit-Pauli Hamiltonian. This enables a treatment of spin, through coherent spin states, which is the first model to use this approach in strong-field physics. We are able to show that the most energetically rescattered wave packets are effected by relativistic kinetic energy corrections during rescattering. We probe these effects and show that they yield notable differences for a 1600-nm wavelength laser field on the dynamics and the photoelectron spectra. Furthermore, we find that the dynamical spin-orbit coupling is strongly overestimated if relativistic corrections to kinetic energy are not considered. Finally, we derive a new condition that demonstrates that relativistic effects begin to play a role at intensities many orders of magnitude lower than expected for the case of rescatterering. Our findings may have important implications for imaging processes such as laser-induced electron diffraction, which includes high-energy photoelectron recollisions.
{"title":"Relativistic and spin-orbit dynamics at nonrelativistic intensities in strong-field ionization","authors":"Andrew S. Maxwell, Lars Bojer Madsen","doi":"10.1103/physreva.110.033108","DOIUrl":"https://doi.org/10.1103/physreva.110.033108","url":null,"abstract":"Spin-orbit dynamics and relativistic corrections to the kinetic energy in strong-field dynamics have long been ignored for near- and mid-infrared fields with intensities <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msup><mn>10</mn><mn>13</mn></msup><mtext>–</mtext><msup><mn>10</mn><mn>14</mn></msup><mspace width=\"0.28em\"></mspace><mi mathvariant=\"normal\">W</mi><mo>/</mo><msup><mrow><mi>cm</mi></mrow><mn>2</mn></msup></mrow></math>, as the final photoelectron energies are considered too low for these effects to play a role. However, using a precise and flexible path-integral formalism, we include all correction terms from the fine-structure, Breit-Pauli Hamiltonian. This enables a treatment of spin, through coherent spin states, which is the first model to use this approach in strong-field physics. We are able to show that the most energetically rescattered wave packets are effected by relativistic kinetic energy corrections during rescattering. We probe these effects and show that they yield notable differences for a 1600-nm wavelength laser field on the dynamics and the photoelectron spectra. Furthermore, we find that the dynamical spin-orbit coupling is strongly overestimated if relativistic corrections to kinetic energy are not considered. Finally, we derive a new condition that demonstrates that relativistic effects begin to play a role at intensities many orders of magnitude lower than expected for the case of rescatterering. Our findings may have important implications for imaging processes such as laser-induced electron diffraction, which includes high-energy photoelectron recollisions.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"27 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262621","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/physreva.110.032212
S. L. Wu, W. Ma, Lian-Ao Wu
We present a method aimed at protecting unitary dynamics in the presence of decoherence, by integrating leakage elimination operators (LEOs) into the system's evolution to create dynamical leakage-free paths. Deriving the dynamical equation for an open quantum system with general drives can be challenging. Our approach avoids the rotating wave approximation and instead uses the coarse-grained averaging technique to derive a quantum master equation for such systems. The combination of the coarse-graining approach and LEO operators appears suitable to study Markovian control methods. We show that employing LEO pulses in specific subspaces can reduce errors arising from undesired transitions due to decoherence. Notably, satisfactory final fidelity can still be achieved even when the reservoir is at a finite temperature. By looking into the dynamical equation governing the quantum state on the dynamical leakage-free path, we provide analytical insights into the effectiveness of the LEO method in suppressing decoherence effects.
我们提出了一种方法，旨在通过将泄漏消除算子（LEOs）整合到系统的演化过程中来创建动态无泄漏路径，从而在存在退相干的情况下保护单元动力学。推导具有一般驱动力的开放量子系统的动力学方程具有挑战性。我们的方法避免了旋转波近似，而是使用粗粒度平均技术来推导此类系统的量子主方程。粗粒化方法与 LEO 算子的结合似乎适合研究马尔可夫控制方法。我们的研究表明，在特定子空间中使用 LEO 脉冲可以减少由于退相干引起的非预期转换所产生的误差。值得注意的是，即使在储层温度有限的情况下，仍然可以实现令人满意的最终保真度。通过研究动态无泄漏路径上量子态的动力学方程，我们对 LEO 方法在抑制退相干效应方面的有效性有了分析性的认识。
{"title":"Creating dynamic leakage-free paths using coarse-graining techniques in the presence of decoherence","authors":"S. L. Wu, W. Ma, Lian-Ao Wu","doi":"10.1103/physreva.110.032212","DOIUrl":"https://doi.org/10.1103/physreva.110.032212","url":null,"abstract":"We present a method aimed at protecting unitary dynamics in the presence of decoherence, by integrating leakage elimination operators (LEOs) into the system's evolution to create dynamical leakage-free paths. Deriving the dynamical equation for an open quantum system with general drives can be challenging. Our approach avoids the rotating wave approximation and instead uses the coarse-grained averaging technique to derive a quantum master equation for such systems. The combination of the coarse-graining approach and LEO operators appears suitable to study Markovian control methods. We show that employing LEO pulses in specific subspaces can reduce errors arising from undesired transitions due to decoherence. Notably, satisfactory final fidelity can still be achieved even when the reservoir is at a finite temperature. By looking into the dynamical equation governing the quantum state on the dynamical leakage-free path, we provide analytical insights into the effectiveness of the LEO method in suppressing decoherence effects.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"30 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205851","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/physreva.110.032614
Tian-Niu Xu, Yongcheng Ding, José D. Martín-Guerrero, Xi Chen
In the realm of quantum control, reinforcement learning, a prominent branch of machine learning, emerges as a competitive candidate for computer-assisted optimal experiment design. This paper investigates the extent to which guidance from human experts is necessary for effectively implementing reinforcement learning in the design of quantum control protocols. Specifically, our focus lies on engineering a robust two-qubit gate, utilizing a combination of analytical solutions as prior knowledge and techniques from computer science. Through thorough benchmarking of various models, we identify dropout—a widely used method for mitigating overfitting in machine learning—as a particularly robust approach. Our findings demonstrate the potential of integrating computer science concepts to propel the development of advanced quantum technologies.
{"title":"Robust two-qubit gate with reinforcement learning and dropout","authors":"Tian-Niu Xu, Yongcheng Ding, José D. Martín-Guerrero, Xi Chen","doi":"10.1103/physreva.110.032614","DOIUrl":"https://doi.org/10.1103/physreva.110.032614","url":null,"abstract":"In the realm of quantum control, reinforcement learning, a prominent branch of machine learning, emerges as a competitive candidate for computer-assisted optimal experiment design. This paper investigates the extent to which guidance from human experts is necessary for effectively implementing reinforcement learning in the design of quantum control protocols. Specifically, our focus lies on engineering a robust two-qubit gate, utilizing a combination of analytical solutions as prior knowledge and techniques from computer science. Through thorough benchmarking of various models, we identify dropout—a widely used method for mitigating overfitting in machine learning—as a particularly robust approach. Our findings demonstrate the potential of integrating computer science concepts to propel the development of advanced quantum technologies.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"102 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142262619","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/physreva.110.032612
William K. Schenken, Simon A. Meynell, Francisco Machado, Bingtian Ye, Claire A. McLellan, Maxime Joos, V. V. Dobrovitski, Norman Y. Yao, Ania C. Bleszynski Jayich
Periodic driving has emerged as a powerful tool to control, engineer, and characterize many-body quantum systems. However, the required pulse sequences are often complex, long, or require the ability to control the individual degrees of freedom. In this work, we study how a simple Carr-Purcell–Meiboom-Gill (CPMG)-like pulse sequence can be leveraged to enhance the coherence of a large ensemble of spin qubits and serve as an important characterization tool. We implement the periodic drive on an ensemble of dense nitrogen-vacancy (NV) centers in diamond and examine the effect of pulse rotation offset as a control parameter on the dynamics. We use a single diamond sample prepared with several spots of varying NV density, which, in turn, varies the NV-NV dipolar interaction strength. Counterintuitively, we find that rotation offsets deviating from the ideal pulse in the CPMG sequence (often classified as pulse errors) play a critical role in preserving coherence along an axis set by the pulses even at nominally zero rotation offset. The cause of the coherence preservation is an emergent effective field that scales linearly with the magnitude of the rotation offset for small offsets. In addition to extending coherence, we compare the rotation offset dependence of coherence to numerical simulations to measure the disorder and dipolar contributions to the Hamiltonian to quantitatively extract the densities of the constituent spin species within the diamond.
{"title":"Long-lived coherences in strongly interacting spin ensembles","authors":"William K. Schenken, Simon A. Meynell, Francisco Machado, Bingtian Ye, Claire A. McLellan, Maxime Joos, V. V. Dobrovitski, Norman Y. Yao, Ania C. Bleszynski Jayich","doi":"10.1103/physreva.110.032612","DOIUrl":"https://doi.org/10.1103/physreva.110.032612","url":null,"abstract":"Periodic driving has emerged as a powerful tool to control, engineer, and characterize many-body quantum systems. However, the required pulse sequences are often complex, long, or require the ability to control the individual degrees of freedom. In this work, we study how a simple Carr-Purcell–Meiboom-Gill (CPMG)-like pulse sequence can be leveraged to enhance the coherence of a large ensemble of spin qubits and serve as an important characterization tool. We implement the periodic drive on an ensemble of dense nitrogen-vacancy (NV) centers in diamond and examine the effect of pulse rotation offset as a control parameter on the dynamics. We use a single diamond sample prepared with several spots of varying NV density, which, in turn, varies the NV-NV dipolar interaction strength. Counterintuitively, we find that rotation offsets deviating from the ideal <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>π</mi></math> pulse in the CPMG sequence (often classified as pulse errors) play a critical role in preserving coherence along an axis set by the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>π</mi></math> pulses even at nominally zero rotation offset. The cause of the coherence preservation is an emergent effective field that scales linearly with the magnitude of the rotation offset for small offsets. In addition to extending coherence, we compare the rotation offset dependence of coherence to numerical simulations to measure the disorder and dipolar contributions to the Hamiltonian to quantitatively extract the densities of the constituent spin species within the diamond.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"404 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205850","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/physreva.110.032413
Dong-Sheng Wang, Yuan-Dong Liu, Yun-Jiang Wang, Shunlong Luo
Error-correction codes are central for fault-tolerant information processing. Here we develop a rigorous framework to describe various coding models based on quantum resource theory of superchannels. We find, by treating codings as superchannels, a hierarchy of coding models can be established, including the entanglement assisted or unassisted settings, and their local versions. We show that these coding models can be used to classify error-correction codes and accommodate different computation and communication settings depending on the data type, side channels, and pre-/postprocessing. We believe the coding hierarchy could also inspire new coding models and error-correction methods.
{"title":"Quantum resource theory of coding for error correction","authors":"Dong-Sheng Wang, Yuan-Dong Liu, Yun-Jiang Wang, Shunlong Luo","doi":"10.1103/physreva.110.032413","DOIUrl":"https://doi.org/10.1103/physreva.110.032413","url":null,"abstract":"Error-correction codes are central for fault-tolerant information processing. Here we develop a rigorous framework to describe various coding models based on quantum resource theory of superchannels. We find, by treating codings as superchannels, a hierarchy of coding models can be established, including the entanglement assisted or unassisted settings, and their local versions. We show that these coding models can be used to classify error-correction codes and accommodate different computation and communication settings depending on the data type, side channels, and pre-/postprocessing. We believe the coding hierarchy could also inspire new coding models and error-correction methods.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"7 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205857","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 collective charge of two-level atoms interacting in an open system is investigated. In contrast to a no atomic dissipation quantum battery, the battery remains at a steady state after reaching the moment of full charge. Considering the interactions between atoms, we find that the energy storage of quantum batteries will be significantly enhanced with the increase of atomic repulsion, and the attraction between atoms will exacerbate the dissipation of batteries in the environment. We extend this conclusion to two-level batteries in the drive field and three-level atom quantum batteries. In addition, we also investigate the dissipative charging process of multiatom quantum batteries and find that the number of atoms during the charging process can to some extent affect the energy conversion efficiency during the charging process. Under extreme conditions, the inverse temperature can disrupt the energy storage of the battery.
研究了在开放系统中相互作用的 N 个两级原子的集体电荷。与无原子耗散量子电池相比，电池在达到满电时刻后保持稳定状态。考虑到原子间的相互作用，我们发现量子电池的能量存储会随着原子斥力的增加而显著增强，原子间的吸引力会加剧电池在环境中的耗散。我们将这一结论推广到驱动场中的两级电池和三级原子量子电池。此外，我们还研究了多原子量子电池的耗散充电过程，发现充电过程中的原子数量会在一定程度上影响充电过程中的能量转换效率。在极端条件下，反温度 β 会破坏电池的能量存储。
{"title":"Quantum battery with interactive atomic collective charging","authors":"Dayang Zhang, Shuangquan Ma, Yunxiu Jiang, Youbin Yu, Guangri Jin, Aixi Chen","doi":"10.1103/physreva.110.032211","DOIUrl":"https://doi.org/10.1103/physreva.110.032211","url":null,"abstract":"The collective charge of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>N</mi></math> two-level atoms interacting in an open system is investigated. In contrast to a no atomic dissipation quantum battery, the battery remains at a steady state after reaching the moment of full charge. Considering the interactions between atoms, we find that the energy storage of quantum batteries will be significantly enhanced with the increase of atomic repulsion, and the attraction between atoms will exacerbate the dissipation of batteries in the environment. We extend this conclusion to two-level batteries in the drive field and three-level atom quantum batteries. In addition, we also investigate the dissipative charging process of multiatom quantum batteries and find that the number of atoms during the charging process can to some extent affect the energy conversion efficiency during the charging process. Under extreme conditions, the inverse temperature <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>β</mi></math> can disrupt the energy storage of the battery.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"10 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205858","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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