Lü Xiang, He Wang, Zi-Meng Li, Zhu-Cheng Zhang, Yi-Ping Wang
{"title":"Back Cover: Triggering and Modulation of Quantum Magnon-Photon Hall Insulator in a 1D Cavity Magnonics Lattice (Adv. Quantum Technol. 9/2024)","authors":"Lü Xiang, He Wang, Zi-Meng Li, Zhu-Cheng Zhang, Yi-Ping Wang","doi":"10.1002/qute.202470026","DOIUrl":"https://doi.org/10.1002/qute.202470026","url":null,"abstract":"<p>In article number 2400111, Zhu-Cheng Zhang, Yi-Ping Wang, and co-workers propose a scheme for implementing a one-dimensional cavity magnonics lattice that exhibits quantum magnon–photon Hall insulator behaviors. By adjusting corresponding parameters, different energy spectrum structures can be triggered, and the flipping of edge states can be observed, enabling multi-channel topological quantum state transmission.\u0000\u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure></p>","PeriodicalId":72073,"journal":{"name":"Advanced quantum technologies","volume":"7 9","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/qute.202470026","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142170163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"High-Dimensional Photonic Quantum Computing with a Measurement-Free Auxiliary System","authors":"Xue-Mei Ren, Fang-Fang Du","doi":"10.1002/qute.202400208","DOIUrl":"10.1002/qute.202400208","url":null,"abstract":"<p>Enhancing the capabilities of quantum computing relies heavily on harnessing the power of qudit-based high-dimensional quantum gates. In the study, single-qudit 4D <span></span><math>\u0000 <semantics>\u0000 <mi>X</mi>\u0000 <annotation>$ X$</annotation>\u0000 </semantics></math>, <span></span><math>\u0000 <semantics>\u0000 <msup>\u0000 <mi>X</mi>\u0000 <mn>2</mn>\u0000 </msup>\u0000 <annotation>$ X^{2}$</annotation>\u0000 </semantics></math>, and <span></span><math>\u0000 <semantics>\u0000 <msup>\u0000 <mi>X</mi>\u0000 <mo>†</mo>\u0000 </msup>\u0000 <annotation>$ X^{dagger }$</annotation>\u0000 </semantics></math> gates tailored for a two-photon system in polarization states are presented. Furthermore, a two-qudit <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>4</mn>\u0000 <mo>×</mo>\u0000 <mn>4</mn>\u0000 </mrow>\u0000 <annotation>$4times 4$</annotation>\u0000 </semantics></math>-dimensional controlled-not (CNOT) gate designed for a four-photon system is introduced. These high-dimensional gates can offer versatile and straightforward optical implementations, ensuring them to fulfill in a deterministic way. To facilitate these processes, an auxiliary system in the form of a <span></span><math>\u0000 <semantics>\u0000 <mi>Λ</mi>\u0000 <annotation>$Lambda$</annotation>\u0000 </semantics></math>-type atom residing in a cavity is employed. Remarkably, the auxiliary system retains its original state after the operation process ends, so it is not required to measure and plays a pivotal role in promoting effective interactions among distinct photons in its extended coherence time. Importantly, the in-depth analysis of the fidelities and efficiencies of these quantum gates showcase remarkable outcomes, affirming the superiority of the proposed protocols. Therefore, these high-dimensional gates not only amplify quantum parallelism, but also bolster the speed of quantum computations, fortify resilience against errors, and foster scalability for executing intricate quantum operations.</p>","PeriodicalId":72073,"journal":{"name":"Advanced quantum technologies","volume":"7 11","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rafael I. Nepomechie, Francesco Ravanini, David Raveh
{"title":"Spin-\u0000 \u0000 s\u0000 $s$\u0000 Dicke States and Their Preparation","authors":"Rafael I. Nepomechie, Francesco Ravanini, David Raveh","doi":"10.1002/qute.202400057","DOIUrl":"10.1002/qute.202400057","url":null,"abstract":"<p>The notion of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>s</mi>\u0000 <mi>u</mi>\u0000 <mo>(</mo>\u0000 <mn>2</mn>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <annotation>$su(2)$</annotation>\u0000 </semantics></math> spin-<span></span><math>\u0000 <semantics>\u0000 <mi>s</mi>\u0000 <annotation>$s$</annotation>\u0000 </semantics></math> Dicke states is introduced, which are higher-spin generalizations of usual (spin-1/2) Dicke states. These multi-qudit states can be expressed as superpositions of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>s</mi>\u0000 <mi>u</mi>\u0000 <mo>(</mo>\u0000 <mn>2</mn>\u0000 <mi>s</mi>\u0000 <mo>+</mo>\u0000 <mn>1</mn>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <annotation>$su(2s+1)$</annotation>\u0000 </semantics></math> qudit Dicke states. They satisfy a recursion formula, which is used to formulate an efficient quantum circuit for their preparation, whose size scales as <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>s</mi>\u0000 <mi>k</mi>\u0000 <mo>(</mo>\u0000 <mn>2</mn>\u0000 <mi>s</mi>\u0000 <mi>n</mi>\u0000 <mo>−</mo>\u0000 <mi>k</mi>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <annotation>$sk(2sn-k)$</annotation>\u0000 </semantics></math>, where <span></span><math>\u0000 <semantics>\u0000 <mi>n</mi>\u0000 <annotation>$n$</annotation>\u0000 </semantics></math> is the number of qudits and <span></span><math>\u0000 <semantics>\u0000 <mi>k</mi>\u0000 <annotation>$k$</annotation>\u0000 </semantics></math> is the number of times the total spin-lowering operator is applied to the highest-weight state. The algorithm is deterministic and does not require ancillary qudits.</p>","PeriodicalId":72073,"journal":{"name":"Advanced quantum technologies","volume":"7 12","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/qute.202400057","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}