Quantum最新文献_第2页

Piquasso: A Photonic Quantum Computer Simulation Software Platform

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-04-15 DOI: 10.22331/q-2025-04-15-1708

Zoltán Kolarovszki, Tomasz Rybotycki, Péter Rakyta, Ágoston Kaposi, Boldizsár Poór, Szabolcs Jóczik, Dániel T. R. Nagy, Henrik Varga, Kareem H. El-Safty, Gregory Morse, Michał Oszmaniec, Tamás Kozsik, Zoltán Zimborás

引用次数: 0

Parallel repetition of local simultaneous state discrimination

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-04-15 DOI: 10.22331/q-2025-04-15-1706

Llorenç Escolà-Farràs, Jaròn Has, Maris Ozols, Christian Schaffner, Mehrdad Tahmasbi

{"title":"Parallel repetition of local simultaneous state discrimination","authors":"Llorenç Escolà-Farràs, Jaròn Has, Maris Ozols, Christian Schaffner, Mehrdad Tahmasbi","doi":"10.22331/q-2025-04-15-1706","DOIUrl":"https://doi.org/10.22331/q-2025-04-15-1706","url":null,"abstract":"Local simultaneous state discrimination (LSSD) is a recently introduced problem in quantum information processing. Its classical version is a non-local game played by non-communicating players against a referee. Based on a known probability distribution, the referee generates one input for each of the players and keeps one secret value. The players have to guess the referee's value and win if they all do so. For this game, we investigate the advantage of no-signalling strategies over classical ones. We show numerically that for three players and binary values, no-signalling strategies cannot provide any improvement over classical ones. For a certain LSSD game based on a binary symmetric channel, we show that no-signalling strategies are strictly better when multiple simultaneous instances of the game are played. Good classical strategies for this game can be defined by codes, and good no-signalling strategies by list-decoding schemes. We expand this example game to a class of games defined by an arbitrary channel, and extend the idea of using codes and list decoding to define strategies for multiple simultaneous instances of these games. Finally, we give an expression for the limit of the exponent of the classical winning probability, and show that no-signalling strategies based on list-decoding schemes achieve this limit.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"8 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Classifying fermionic states via many-body correlation measures 通过多体相关测量对费米子态进行分类

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-04-15 DOI: 10.22331/q-2025-04-15-1705

Mykola Semenyakin, Yevheniia Cheipesh, Yaroslav Herasymenko

{"title":"Classifying fermionic states via many-body correlation measures","authors":"Mykola Semenyakin, Yevheniia Cheipesh, Yaroslav Herasymenko","doi":"10.22331/q-2025-04-15-1705","DOIUrl":"https://doi.org/10.22331/q-2025-04-15-1705","url":null,"abstract":"Understanding the structure of quantum correlations in a many-body system is key to its computational treatment. For fermionic systems, correlations can be defined as deviations from Slater determinant states. The link between fermionic correlations and efficient computational physics methods is actively studied but remains ambiguous. We make progress in establishing this connection mathematically. In particular, we find a rigorous classification of states relative to $k$-fermion correlations, which admits a computational physics interpretation. Correlations are captured by a measure $omega_k$, a function of $k$-fermion reduced density matrix that we call twisted purity. A condition $omega_k=0$ for a given $k$ puts the state in a class $G_k$ of correlated states. Sets $G_k$ are nested in $k$, and Slater determinants correspond to $k = 1$. Classes $G_{k=O(1)}$ are shown to be physically relevant, as $omega_k$ vanishes or nearly vanishes for truncated configuration-interaction states, perturbation series around Slater determinants, and some nonperturbative eigenstates of the 1D Hubbard model. For each $k = O(1)$, we give an explicit ansatz with a polynomial number of parameters that covers all states in $G_k$. Potential applications of this ansatz and its connections to the coupled-cluster wavefunction are discussed.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"10 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The coherent measurement cost of coherence distillation

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-04-15 DOI: 10.22331/q-2025-04-15-1707

Varun Narasimhachar

{"title":"The coherent measurement cost of coherence distillation","authors":"Varun Narasimhachar","doi":"10.22331/q-2025-04-15-1707","DOIUrl":"https://doi.org/10.22331/q-2025-04-15-1707","url":null,"abstract":"Quantum coherence—an indispensable resource for quantum technologies—is known to be distillable from a noisy form using operations that cannot create it. However, distillation exacts a hidden coherent $measurement$ cost, which has not previously been examined. We devise the $textit{target effect}$ construction to characterize this cost through detailed conditions on the coherence-measuring structure necessary in any process realizing exact (maximal or non-maximal) or approximate distillation. As a corollary, we lower-bound the requisite measurement coherence, as quantified by operationally-relevant measures. We then consider the asymptotic limit of distilling from many copies of a given noisy coherent state, where we offer rigorous arguments to support the conjecture that the (necessary and sufficient) coherent measurement cost scales extensively in the number of copies. We also show that this cost is no smaller than the coherence of measurements saturating the scaling law in the generalized quantum Stein's lemma. Our results and conjectures apply to any task whereof coherence distillation is an incidental outcome (e.g., incoherent randomness extraction). But if pure coherence is the only desired outcome, our conjectures would have the cautionary implication that the measurement cost is often higher than the distilled yield, in which case coherence should rather be prepared afresh than distilled from a noisy input.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"37 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143836731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Improving entanglement purification through coherent superposition of roles 通过相干叠加作用改进纠缠纯化

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-04-09 DOI: 10.22331/q-2025-04-09-1702

Jorge Miguel-Ramiro, Alexander Pirker, Wolfgang Dür

引用次数: 0

Multi-copy activation of genuine multipartite entanglement in continuous-variable systems

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-04-09 DOI: 10.22331/q-2025-04-09-1699

Klára Baksová, Olga Leskovjanová, Ladislav Mišta Jr., Elizabeth Agudelo, Nicolai Friis

引用次数: 0

Hamiltonian Learning via Shadow Tomography of Pseudo-Choi States 通过伪乔伊状态的影子断层扫描进行哈密顿学习

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-04-09 DOI: 10.22331/q-2025-04-09-1700

Juan Castaneda, Nathan Wiebe

{"title":"Hamiltonian Learning via Shadow Tomography of Pseudo-Choi States","authors":"Juan Castaneda, Nathan Wiebe","doi":"10.22331/q-2025-04-09-1700","DOIUrl":"https://doi.org/10.22331/q-2025-04-09-1700","url":null,"abstract":"We introduce a new approach to learn Hamiltonians through a resource that we call the pseudo-Choi state, which encodes the Hamiltonian in a state using a procedure that is analogous to the Choi-Jamiolkowski isomorphism. We provide an efficient method for generating these pseudo-Choi states by querying a time evolution unitary of the form $e^{-iHt}$ and its inverse, and show that for a Hamiltonian with $M$ terms the Hamiltonian coefficients can be estimated via classical shadow tomography within error $epsilon$ in the $2$-norm using $widetilde{O}left(frac{M}{t^2epsilon^2}right)$ queries to the state preparation protocol, where $t le frac{1}{2leftlVert H rightrVert}$. We further show an alternative approach that eschews classical shadow tomography in favor of quantum mean estimation that reduces this cost (at the price of many more qubits) to $widetilde{O}left(frac{M}{tepsilon}right)$. Additionally, we show that in the case where one does not have access to the state preparation protocol, the Hamiltonian can be learned using $widetilde{O}left(frac{alpha^4M}{epsilon^2}right)$ copies of the pseudo-Choi state. The constant $alpha$ depends on the norm of the Hamiltonian, and the scaling in terms of $alpha$ can be improved quadratically if using pseudo-Choi states of the normalized Hamiltonian. Finally, we show that our learning process is robust to errors in the resource states and to errors in the Hamiltonian class. Specifically, we show that if the true Hamiltonian contains more terms than we believe are present in the reconstruction, then our methods give an indication that there are Hamiltonian terms that have not been identified and will still accurately estimate the known terms in the Hamiltonian.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"31 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143805866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Accurate and Honest Approximation of Correlated Qubit Noise

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-04-09 DOI: 10.22331/q-2025-04-09-1701

Setiawan F., Alexander V. Gramolin, Elisha S. Matekole, Hari Krovi, Jacob M. Taylor

{"title":"Accurate and Honest Approximation of Correlated Qubit Noise","authors":"Setiawan F., Alexander V. Gramolin, Elisha S. Matekole, Hari Krovi, Jacob M. Taylor","doi":"10.22331/q-2025-04-09-1701","DOIUrl":"https://doi.org/10.22331/q-2025-04-09-1701","url":null,"abstract":"Accurate modeling of noise in realistic quantum processors is critical for constructing fault-tolerant quantum computers. While a full simulation of actual noisy quantum circuits provides information about correlated noise among all qubits and is therefore accurate, it is, however, computationally expensive as it requires resources that grow exponentially with the number of qubits. We propose an efficient systematic construction of approximate noise channels, where their accuracy can be enhanced by incorporating noise components with higher qubit-qubit correlation degree. To formulate such approximate channels, we first present a method, dubbed the cluster expansion approach, to decompose the Lindbladian generator of an actual noise channel into components based on interqubit correlation degree. We generate a $k$-th order approximate noise channel by truncating the cluster expansion and incorporating noise components with correlations up to the $k$-th degree. We require that the approximate noise channels must be accurate and also “honest\", i.e., the actual errors are not underestimated in our physical models. As an example application, we apply our method to model noise in a three-qubit quantum processor that stabilizes a [[2,0,2]] codeword, which is one of the four Bell states. We find that, for realistic noise strength typical for fixed-frequency superconducting qubits coupled via always-on static interactions, correlated noise beyond two-qubit correlation can significantly affect the code simulation accuracy. Since our approach provides a systematic characterization of multi-qubit noise correlations, it enables the potential for accurate, honest and scalable approximations to simulate large numbers of qubits from full modeling or experimental characterizations of small enough quantum subsystems, which are efficient yet still retain essential noise features of the entire device.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"183 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143805869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Quantum state preparation for multivariate functions

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-04-09 DOI: 10.22331/q-2025-04-09-1703

Matthias Rosenkranz, Eric Brunner, Gabriel Marin-Sanchez, Nathan Fitzpatrick, Silas Dilkes, Yao Tang, Yuta Kikuchi, Marcello Benedetti

引用次数: 0

Ground state energy and magnetization curve of a frustrated magnetic system from real-time evolution on a digital quantum processor 从数字量子处理器上的实时演化看挫折磁系统的基态能量和磁化曲线

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-04-09 DOI: 10.22331/q-2025-04-09-1704

Aaron Szasz, Ed Younis, Wibe Albert de Jong

{"title":"Ground state energy and magnetization curve of a frustrated magnetic system from real-time evolution on a digital quantum processor","authors":"Aaron Szasz, Ed Younis, Wibe Albert de Jong","doi":"10.22331/q-2025-04-09-1704","DOIUrl":"https://doi.org/10.22331/q-2025-04-09-1704","url":null,"abstract":"Models of interacting many-body quantum systems that may realize new exotic phases of matter, notably quantum spin liquids, are challenging to study using even state-of-the-art classical methods such as tensor network simulations. Quantum computing provides a promising route for overcoming these difficulties to find ground states, dynamics, and more. In this paper, we argue that recently developed hybrid quantum-classical algorithms based on real-time evolution are promising methods for solving a particularly important model in the search for spin liquids, the antiferromagnetic Heisenberg model on the two-dimensional kagome lattice. We show how to construct efficient quantum circuits to implement time evolution for the model and to evaluate key observables on the quantum computer, and we argue that the method has favorable scaling with increasing system size. We then restrict to a 12-spin star plaquette from the kagome lattice and a related 8-spin system, and we give an empirical demonstration on these small systems that the hybrid algorithms can efficiently find the ground state energy and the magnetization curve. For these demonstrations, we use four levels of approximation: exact state vectors, exact state vectors with statistical noise from sampling, noisy classical emulators, and (for the 8-spin system only) real quantum hardware, specifically the Quantinuum H1-1 processor; for the noisy simulations and hardware demonstration, we also employ error mitigation strategies based on the symmetries of the Hamiltonian. Our results strongly suggest that these hybrid algorithms present a promising direction for studying quantum spin liquids and more generally for resolving important unsolved problems in condensed matter theory and beyond.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"31 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143813898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0