Pub Date : 2024-09-11DOI: 10.1103/physreva.110.033712
Agustina G. Magnoni, Laura T. Knoll, Lina Wölcken, Julián Defant, Julián Morales, Miguel A. Larotonda
We demonstrate the feasibility of implementing a photon source with sub-Poissonian emission statistics through temporal multiplexing of a continuous wave heralded photon source in the optical communications wavelength range. We use the time arrival information of a heralding photon to actively modify the delay of the heralded photon in an all-fiber assembly, in order to synchronize the output with respect to an external clock. Within this synchronized operating regime we show that the addition of a single temporal correcting stage can improve the figure of merit for single-photon emission of a heralded photon source. We obtain a brightness improvement factor of approximately 1.8 and an enhancement of the signal-to-noise ratio, quantified by the coincidence-to-accidental counts ratio. These results clear the way for integrated optics nonclassical photon sources in the optical communication band.
{"title":"Toward an optical-fiber-based temporally multiplexed single-photon source","authors":"Agustina G. Magnoni, Laura T. Knoll, Lina Wölcken, Julián Defant, Julián Morales, Miguel A. Larotonda","doi":"10.1103/physreva.110.033712","DOIUrl":"https://doi.org/10.1103/physreva.110.033712","url":null,"abstract":"We demonstrate the feasibility of implementing a photon source with sub-Poissonian emission statistics through temporal multiplexing of a continuous wave heralded photon source in the optical communications wavelength range. We use the time arrival information of a heralding photon to actively modify the delay of the heralded photon in an all-fiber assembly, in order to synchronize the output with respect to an external clock. Within this synchronized operating regime we show that the addition of a single temporal correcting stage can improve the figure of merit for single-photon emission of a heralded photon source. We obtain a brightness improvement factor of approximately 1.8 and an enhancement of the signal-to-noise ratio, quantified by the coincidence-to-accidental counts ratio. These results clear the way for integrated optics nonclassical photon sources in the optical communication band.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"45 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205871","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 : 2024-09-11DOI: 10.1103/physreva.110.032411
Balint Pato, Theerapat Tansuwannont, Kenneth R. Brown
A fault-tolerant error correction (FTEC) protocol with a high error suppression rate and low overhead is very desirable for the near-term implementation of quantum computers. In this work, we develop a distance-preserving flag FTEC protocol for the concatenated Steane code, which requires only two ancilla qubits per generator and can be implemented on a planar layout. We generalize the weight-parity error correction (WPEC) technique from Tansuwannont and Leung [Phys. Rev. A104, 042410 (2021)] and find a gate ordering of flag circuits for the concatenated Steane code, which makes syndrome extraction with two ancilla qubits per generator possible. The FTEC protocol is constructed using the optimization tools for flag FTEC developed in Pato et al. [PRX Quantum5, 020336 (2024)] and is simulated under the circuit-level noise model without idling noise. Our simulations give a pseudothreshold of for the concatenated Steane code, which is better than a pseudothreshold of for the 6.6.6 color code simulated under the same settings. This is in contrast to the code capacity model where the code performs better.
{"title":"Concatenated Steane code with single-flag syndrome checks","authors":"Balint Pato, Theerapat Tansuwannont, Kenneth R. Brown","doi":"10.1103/physreva.110.032411","DOIUrl":"https://doi.org/10.1103/physreva.110.032411","url":null,"abstract":"A fault-tolerant error correction (FTEC) protocol with a high error suppression rate and low overhead is very desirable for the near-term implementation of quantum computers. In this work, we develop a distance-preserving flag FTEC protocol for the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mo>[</mo><mo>[</mo><mn>49</mn><mo>,</mo><mn>1</mn><mo>,</mo><mn>9</mn><mo>]</mo><mo>]</mo></mrow></math> concatenated Steane code, which requires only two ancilla qubits per generator and can be implemented on a planar layout. We generalize the weight-parity error correction (WPEC) technique from Tansuwannont and Leung [<span>Phys. Rev. A</span> <b>104</b>, 042410 (2021)] and find a gate ordering of flag circuits for the concatenated Steane code, which makes syndrome extraction with two ancilla qubits per generator possible. The FTEC protocol is constructed using the optimization tools for flag FTEC developed in Pato <i>et al.</i> [<span>PRX Quantum</span> <b>5</b>, 020336 (2024)] and is simulated under the circuit-level noise model without idling noise. Our simulations give a pseudothreshold of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>1.64</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>3</mn></mrow></msup></mrow></math> for the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mo>[</mo><mo>[</mo><mn>49</mn><mo>,</mo><mn>1</mn><mo>,</mo><mn>9</mn><mo>]</mo><mo>]</mo></mrow></math> concatenated Steane code, which is better than a pseudothreshold of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>1.43</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>3</mn></mrow></msup></mrow></math> for the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mo>[</mo><mo>[</mo><mn>61</mn><mo>,</mo><mn>1</mn><mo>,</mo><mn>9</mn><mo>]</mo><mo>]</mo></mrow></math> 6.6.6 color code simulated under the same settings. This is in contrast to the code capacity model where the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mo>[</mo><mo>[</mo><mn>61</mn><mo>,</mo><mn>1</mn><mo>,</mo><mn>9</mn><mo>]</mo><mo>]</mo></mrow></math> code performs better.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"45 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205863","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 : 2024-09-11DOI: 10.1103/physreva.110.033711
Muhammad Waseem, Muhammad Irfan, Shahid Qamar
Phenomena involving interactions among magnons, phonons, and photons in cavity magnomechanical systems have attracted considerable attention recently, owing to their potential applications in the microwave frequency range. One such important effect is the response of a probe field to such a tripartite interaction between photon-magnon-phonon. In this paper we study the Goos-Hänchen shift (GHS) of a reflected probe field in a cavity magnomechanical system. We consider a yttrium iron garnet (YIG) sphere positioned within a microwave cavity. A microwave control field directly drives the magnon mode in the YIG sphere, whereas the cavity is driven via a weak probe field. Our results show that the GHS can be coherently controlled through magnon-phonon coupling via the control field. For instance, the GHS can be tuned from positive to negative by tuning the magnon-phonon coupling. Similarly, the effective cavity detuning is another important controlling parameter for the GHS. Furthermore, we observe that the enhancement of the GHS occurs when magnon-phonon coupling is weak at resonance and when the magnon-photon coupling is approximately equal to the loss of microwave photons. Our findings may have potential significance in applications related to microwave switching and sensing.
{"title":"Magnomechanically controlled Goos-Hänchen shift in cavity QED","authors":"Muhammad Waseem, Muhammad Irfan, Shahid Qamar","doi":"10.1103/physreva.110.033711","DOIUrl":"https://doi.org/10.1103/physreva.110.033711","url":null,"abstract":"Phenomena involving interactions among magnons, phonons, and photons in cavity magnomechanical systems have attracted considerable attention recently, owing to their potential applications in the microwave frequency range. One such important effect is the response of a probe field to such a tripartite interaction between photon-magnon-phonon. In this paper we study the Goos-Hänchen shift (GHS) of a reflected probe field in a cavity magnomechanical system. We consider a yttrium iron garnet (YIG) sphere positioned within a microwave cavity. A microwave control field directly drives the magnon mode in the YIG sphere, whereas the cavity is driven via a weak probe field. Our results show that the GHS can be coherently controlled through magnon-phonon coupling via the control field. For instance, the GHS can be tuned from positive to negative by tuning the magnon-phonon coupling. Similarly, the effective cavity detuning is another important controlling parameter for the GHS. Furthermore, we observe that the enhancement of the GHS occurs when magnon-phonon coupling is weak at resonance and when the magnon-photon coupling is approximately equal to the loss of microwave photons. Our findings may have potential significance in applications related to microwave switching and sensing.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"1 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205868","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 : 2024-09-11DOI: 10.1103/physreva.110.033515
Ryan Hogan, Giulia Marcucci, Akbar Safari, A. Nicholas Black, Boris Braverman, Jeremy Upham, Robert W. Boyd
Fully describing light propagation in a rotating, anisotropic medium with thermal nonlinearity requires modeling the interplay between nonlinear refraction, birefringence, and the nonlinear group index. Incorporating these factors into a generalized coupled nonlinear Schrödinger equation and fitting them to recent experimental results reveals two key relationships: the photon drag effect can have a nonlinear component that is dependent on the motion of the medium, and the temporal dynamics of the moving birefringent nonlinear medium create distorted figure-eight-like transverse trajectories at the output. The beam trajectory can be accurately modeled with a full understanding of the propagation effects. Efficiently modeling these effects and accurately predicting the beam's output position has implications for optimizing applications in velocimetry and beam steering. Understanding the roles of competitive nonlinearities gives insight into the creation or suppression of nonlinear phenomena like self-action effects.
{"title":"Modeling beam propagation in a moving nonlinear medium","authors":"Ryan Hogan, Giulia Marcucci, Akbar Safari, A. Nicholas Black, Boris Braverman, Jeremy Upham, Robert W. Boyd","doi":"10.1103/physreva.110.033515","DOIUrl":"https://doi.org/10.1103/physreva.110.033515","url":null,"abstract":"Fully describing light propagation in a rotating, anisotropic medium with thermal nonlinearity requires modeling the interplay between nonlinear refraction, birefringence, and the nonlinear group index. Incorporating these factors into a generalized coupled nonlinear Schrödinger equation and fitting them to recent experimental results reveals two key relationships: the photon drag effect can have a nonlinear component that is dependent on the motion of the medium, and the temporal dynamics of the moving birefringent nonlinear medium create distorted figure-eight-like transverse trajectories at the output. The beam trajectory can be accurately modeled with a full understanding of the propagation effects. Efficiently modeling these effects and accurately predicting the beam's output position has implications for optimizing applications in velocimetry and beam steering. Understanding the roles of competitive nonlinearities gives insight into the creation or suppression of nonlinear phenomena like self-action effects.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"9 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205867","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 : 2024-09-10DOI: 10.1103/physreva.110.l031703
Gavin Crowder, Lora Ramunno, Stephen Hughes
Single-photon sources (SPSs) are an essential resource for many quantum information technologies. We demonstrate how the inclusion of time-delayed coherent feedback in a scalable waveguide system can significantly improve the two key SPS figures of merit: coherence and indistinguishability. Our feedback protocol is simulated using a quantum trajectory discretized waveguide model which can be used to directly model Hanbury Brown and Twiss (HBT) and Hong-Ou-Mandel (HOM) interferometers. With the proper choice of the round trip phase, the non-Markovian dynamics from the time-delayed feedback improves the indistinguishability of the SPS by up to . We also show how this mechanism suppresses the detrimental effects of off-chip decay and pure dephasing.
{"title":"Improving on-demand single-photon-source coherence and indistinguishability through a time-delayed coherent feedback","authors":"Gavin Crowder, Lora Ramunno, Stephen Hughes","doi":"10.1103/physreva.110.l031703","DOIUrl":"https://doi.org/10.1103/physreva.110.l031703","url":null,"abstract":"Single-photon sources (SPSs) are an essential resource for many quantum information technologies. We demonstrate how the inclusion of time-delayed coherent feedback in a scalable waveguide system can significantly improve the two key SPS figures of merit: coherence and indistinguishability. Our feedback protocol is simulated using a quantum trajectory discretized waveguide model which can be used to directly model Hanbury Brown and Twiss (HBT) and Hong-Ou-Mandel (HOM) interferometers. With the proper choice of the round trip phase, the non-Markovian dynamics from the time-delayed feedback improves the indistinguishability of the SPS by up to <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>57</mn><mo>%</mo></mrow></math>. We also show how this mechanism suppresses the detrimental effects of off-chip decay and pure dephasing.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"23 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205911","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 : 2024-09-10DOI: 10.1103/physreva.110.032807
Tim Ratajczyk, Kristian König, Philipp Bollinger, Tim Lellinger, Victor Varentsov, Wilfried Nörtershäuser, Julien Spahn
We have measured transition frequencies, isotope shifts, and hyperfine-structure splittings in the transitions in stable ions for using collinear laser spectroscopy. Ions were generated by laser ablation in a buffer-gas atmosphere and extracted into vacuum through a nozzle and a pair of radio-frequency funnels. The results obtained are of interest as reference values for on-line measurements of short-lived titanium isotopes and for astrophysical searches for temporal or spatial variations of the fine-structure constant using quasar absorption spectra.
{"title":"Transition frequencies, isotope shifts, and hyperfine structure in 4s→4p transitions of stable Ti+ ions","authors":"Tim Ratajczyk, Kristian König, Philipp Bollinger, Tim Lellinger, Victor Varentsov, Wilfried Nörtershäuser, Julien Spahn","doi":"10.1103/physreva.110.032807","DOIUrl":"https://doi.org/10.1103/physreva.110.032807","url":null,"abstract":"We have measured transition frequencies, isotope shifts, and hyperfine-structure splittings in the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>3</mn><msup><mi>d</mi><mn>2</mn></msup><mrow><msup><mo>(</mo><mn>3</mn></msup><mi>F</mi><mo>)</mo></mrow><mn>4</mn><mi>s</mi><mspace width=\"0.16em\"></mspace><msup><mrow></mrow><mn>4</mn></msup><msub><mi>F</mi><mi>J</mi></msub><mo>→</mo><mn>3</mn><msup><mi>d</mi><mn>2</mn></msup><mrow><msup><mo>(</mo><mn>3</mn></msup><mi>F</mi><mo>)</mo></mrow><mn>4</mn><mi>p</mi><msup><mspace width=\"0.16em\"></mspace><mn>4</mn></msup><msubsup><mi>G</mi><mrow><mi>J</mi><mo>+</mo><mn>1</mn></mrow><mi>o</mi></msubsup></mrow></math> transitions in stable <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mrow><mi>Ti</mi></mrow><mo>+</mo></msup></math> ions for <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>J</mi><mo>=</mo><mfrac><mn>3</mn><mn>2</mn></mfrac><mo>,</mo><mfrac><mn>5</mn><mn>2</mn></mfrac><mo>,</mo><mfrac><mn>7</mn><mn>2</mn></mfrac></mrow></math> using collinear laser spectroscopy. Ions were generated by laser ablation in a buffer-gas atmosphere and extracted into vacuum through a nozzle and a pair of radio-frequency funnels. The results obtained are of interest as reference values for on-line measurements of short-lived titanium isotopes and for astrophysical searches for temporal or spatial variations of the fine-structure constant <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>α</mi></math> using quasar absorption spectra.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"27 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205921","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 : 2024-09-10DOI: 10.1103/physreva.110.032808
Thomas A. Gomez, Mark C. Zammit, Christopher J. Fontes, Igor Bray, Jackson White
The motion of atoms through a magnetic field (due to a change in reference frame) will result in an additional electric field felt by the electrons in that atom. The motional Stark effect is a well-established effect that has been approximately included in calculations of spectra of magnetized plasmas, usually through diagonalizing the Hamiltonian. The motional Stark effect for continuum states is poorly defined due to an overlap integral that results in a Dirac delta function. This paper presents a workaround by evaluating the motional Stark effect in the Green's function within the scattering formalism. We report on some results pertaining to bound-free spectra for white dwarf and neutron star magnetic field strengths. In most cases, resonances in the continuum are shifted and broadened. This behavior has the effect of raising the Rosseland mean opacity in white dwarfs and neutron star atmospheres.
{"title":"Motional Stark effect on bound-free spectra","authors":"Thomas A. Gomez, Mark C. Zammit, Christopher J. Fontes, Igor Bray, Jackson White","doi":"10.1103/physreva.110.032808","DOIUrl":"https://doi.org/10.1103/physreva.110.032808","url":null,"abstract":"The motion of atoms through a magnetic field (due to a change in reference frame) will result in an additional electric field felt by the electrons in that atom. The motional Stark effect is a well-established effect that has been approximately included in calculations of spectra of magnetized plasmas, usually through diagonalizing the Hamiltonian. The motional Stark effect for continuum states is poorly defined due to an overlap integral that results in a Dirac delta function. This paper presents a workaround by evaluating the motional Stark effect in the Green's function within the scattering formalism. We report on some results pertaining to bound-free spectra for white dwarf and neutron star magnetic field strengths. In most cases, resonances in the continuum are shifted and broadened. This behavior has the effect of raising the Rosseland mean opacity in white dwarfs and neutron star atmospheres.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"147 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205912","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}
We study the geometric phase (GP) of a two-level atom coupled to an environment composed of free space and a dielectric nanosphere in thermal and out of thermal equilibrium. We analytically and numerically analyze the optical properties and loss of the dielectric medium, along with the nonequilibrium effects of the environment on the GP. In the weak coupling limit, we find that the correction to the GP depends on the partial local density of photonic states at the atom position, and an effective parameter that emerges out of the nonequilibrium configuration of the system. The GP exhibits a significant enhancement due to the excitation of evanescent surface waves at its resonance frequency. It is shown that the GP acquired by the atomic system out of thermal equilibrium is always bounded between the thermal-equilibrium counterparts. Furthermore, the temperature difference between the nanosphere and free space can play an important role in the GP only at moderate atomic distances from the nanosphere. Our results elegantly demonstrate properties of the GP near material media that can support phononic modes and pave the way for further research of GP as a resource for quantum computation.
我们研究了处于热平衡和非热平衡状态的两级原子与自由空间和介电纳米球组成的环境耦合的几何相（GP）。我们对介电介质的光学特性和损耗，以及环境对 GP 的非平衡效应进行了分析和数值计算。在弱耦合极限下，我们发现对 GP 的修正取决于原子位置处光子态的部分局部密度，以及从系统非平衡构型中产生的有效参数。由于共振频率下的蒸发表面波的激发，GP 呈现出显著的增强。研究表明，原子系统在非热平衡状态下获得的 GP 值总是介于热平衡对应值之间。此外，纳米球与自由空间之间的温差只有在原子与纳米球距离适中时才会对 GP 起重要作用。我们的研究结果优雅地展示了 GP 在支持声子模式的物质介质附近的特性，为进一步研究 GP 作为量子计算资源铺平了道路。
{"title":"Geometric phase of a two-level atom near a dielectric nanosphere out of thermal equilibrium","authors":"Ehsan Amooghorban, Sareh Shahidani, Somaye Mohamadi Abdhvand","doi":"10.1103/physreva.110.033710","DOIUrl":"https://doi.org/10.1103/physreva.110.033710","url":null,"abstract":"We study the geometric phase (GP) of a two-level atom coupled to an environment composed of free space and a dielectric nanosphere in thermal and out of thermal equilibrium. We analytically and numerically analyze the optical properties and loss of the dielectric medium, along with the nonequilibrium effects of the environment on the GP. In the weak coupling limit, we find that the correction to the GP depends on the partial local density of photonic states at the atom position, and an effective parameter that emerges out of the nonequilibrium configuration of the system. The GP exhibits a significant enhancement due to the excitation of evanescent surface waves at its resonance frequency. It is shown that the GP acquired by the atomic system out of thermal equilibrium is always bounded between the thermal-equilibrium counterparts. Furthermore, the temperature difference between the nanosphere and free space can play an important role in the GP only at moderate atomic distances from the nanosphere. Our results elegantly demonstrate properties of the GP near material media that can support phononic modes and pave the way for further research of GP as a resource for quantum computation.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"1 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205917","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 : 2024-09-10DOI: 10.1103/physreva.110.032609
Debora Ramacciotti, Andreea I. Lefterovici, Antonio F. Rotundo
State preparation is a fundamental routine in quantum computation, for which many algorithms have been proposed. Among them, perhaps the simplest one is the Grover-Rudolph algorithm. In this paper we analyze the performance of this algorithm when the state to prepare is sparse. We show that the gate complexity is linear in the number of nonzero amplitudes in the state and quadratic in the number of qubits. We then introduce a simple modification of the algorithm, which makes the dependence on the number of qubits also linear. This is competitive with the best known algorithms for sparse state preparation.
{"title":"Simple quantum algorithm to efficiently prepare sparse states","authors":"Debora Ramacciotti, Andreea I. Lefterovici, Antonio F. Rotundo","doi":"10.1103/physreva.110.032609","DOIUrl":"https://doi.org/10.1103/physreva.110.032609","url":null,"abstract":"State preparation is a fundamental routine in quantum computation, for which many algorithms have been proposed. Among them, perhaps the simplest one is the Grover-Rudolph algorithm. In this paper we analyze the performance of this algorithm when the state to prepare is sparse. We show that the gate complexity is linear in the number of nonzero amplitudes in the state and quadratic in the number of qubits. We then introduce a simple modification of the algorithm, which makes the dependence on the number of qubits also linear. This is competitive with the best known algorithms for sparse state preparation.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"14 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205872","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 : 2024-09-10DOI: 10.1103/physreva.110.032806
M. X. Ma, T. Meng, B. Tu, P. Ma, Y. W. Zhang, L. Liu, J. Xiao, K. Yao, Y. Zou, Y. Wu, J. G. Wang, B. Wei
As one kind of ubiquitous collision system, deserves attentive study due to its theoretical significance in fundamental physics and applied value in fields like astrophysics or plasma physics. Specifically, in the case of the electron capture process, while a considerable number of measurements and calculations have focused on single electron capture, research is still inadequate on the double electron capture which contributes nearly 10% to the overall electron capture. In this work, a two-active-electron semiclassical asymptotic-state close-coupling method is used to calculate the total and state-selective double electron capture cross sections of collisions in the energy range 0.5–100 keV/u, accompanied by experimental measurements in the energy range 2.63–37.5 keV/u with an uncertainty of 16%, in good consistency. These theoretical and experimental data can fill gaps in the database of double electron capture in collisions and provide insights for improving theoretical models in further research.
{"title":"Double electron capture in O6++He collisions","authors":"M. X. Ma, T. Meng, B. Tu, P. Ma, Y. W. Zhang, L. Liu, J. Xiao, K. Yao, Y. Zou, Y. Wu, J. G. Wang, B. Wei","doi":"10.1103/physreva.110.032806","DOIUrl":"https://doi.org/10.1103/physreva.110.032806","url":null,"abstract":"As one kind of ubiquitous collision system, <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msup><mrow><mi mathvariant=\"normal\">O</mi></mrow><mrow><mn>6</mn><mo>+</mo></mrow></msup><mo>+</mo><mi>He</mi></mrow></math> deserves attentive study due to its theoretical significance in fundamental physics and applied value in fields like astrophysics or plasma physics. Specifically, in the case of the electron capture process, while a considerable number of measurements and calculations have focused on single electron capture, research is still inadequate on the double electron capture which contributes nearly 10% to the overall electron capture. In this work, a two-active-electron semiclassical asymptotic-state close-coupling method is used to calculate the total and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>l</mi><mo>−</mo><mi>resolved</mi></mrow></math> state-selective double electron capture cross sections of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msup><mrow><mi mathvariant=\"normal\">O</mi></mrow><mrow><mn>6</mn><mo>+</mo></mrow></msup><mo>+</mo><mi>He</mi></mrow></math> collisions in the energy range 0.5–100 keV/u, accompanied by experimental measurements in the energy range 2.63–37.5 keV/u with an uncertainty of 16%, in good consistency. These theoretical and experimental data can fill gaps in the database of double electron capture in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msup><mrow><mi mathvariant=\"normal\">O</mi></mrow><mrow><mn>6</mn><mo>+</mo></mrow></msup><mo>+</mo><mi>He</mi></mrow></math> collisions and provide insights for improving theoretical models in further research.","PeriodicalId":20146,"journal":{"name":"Physical Review A","volume":"57 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142205870","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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