{"title":"Emergent Liouvillian exceptional points from exact principles","authors":"Shishir Khandelwal, Gianmichele Blasi","doi":"arxiv-2409.08100","DOIUrl":"https://doi.org/arxiv-2409.08100","url":null,"abstract":"Recent years have seen a surge of interest in exceptional points in open\u0000quantum systems. The natural approach in this area has been the use of\u0000Markovian master equations. While the resulting Liouvillian EPs have been seen\u0000in a variety of systems and have been associated to numerous exotic effects, it\u0000is an open question whether such degeneracies and their peculiarities can\u0000persist beyond the validity of master equations. In this work, taking the\u0000example of a dissipative double-quantum-dot system, we show that Heisenberg\u0000equations for our system exhibit the same EPs as the corresponding master\u0000equations. To highlight the importance of this finding, we prove that the\u0000paradigmatic property associated to EPs - critical damping, persists well\u0000beyond the validity of master equations. Our results demonstrate that\u0000Liouvillian EPs can arise from underlying fundamental exact principles, rather\u0000than merely as a consequence of approximations involved in deriving master\u0000equations.","PeriodicalId":501226,"journal":{"name":"arXiv - PHYS - Quantum Physics","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202224","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}
Raffaele R. Severino, Michele Spasaro, Domenico Zito
{"title":"Silicon Spin Qubit Control and Readout Circuits in 22nm FDSOI CMOS","authors":"Raffaele R. Severino, Michele Spasaro, Domenico Zito","doi":"arxiv-2409.08182","DOIUrl":"https://doi.org/arxiv-2409.08182","url":null,"abstract":"This paper investigates the implementation of microwave and mm-wave\u0000integrated circuits for control and readout of electron/hole spin qubits, as\u0000elementary building blocks for future emerging quantum computing technologies.\u0000In particular, it summarizes the most relevant readout and control techniques\u0000of electron/hole spin qubits, addresses the feasibility and reports some\u0000preliminary simulation results of two blocks: transimpedance amplifier (TIA)\u0000and pulse generator (PG). The TIA exhibits a transimpedance gain of 108.5 dB\u0000Ohm over a -3dB bandwidth of 18 GHz, with input-referred noise current spectral\u0000density of 0.89 pA/root(Hz) at 10 GHz. The PG provides a mm-wave sinusoidal\u0000pulse with a minimum duration time of 20 ps.","PeriodicalId":501226,"journal":{"name":"arXiv - PHYS - Quantum Physics","volume":"105 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202221","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}
{"title":"Collaboration Encouraging Quantum Secret Sharing Scheme with Seal Property","authors":"Xiaogang Cheng, Ren Guo","doi":"arxiv-2409.07863","DOIUrl":"https://doi.org/arxiv-2409.07863","url":null,"abstract":"A new concept of quantum secret sharing is introduced, in which collaboration\u0000among participants are encourage. And the dealer can ask the participants to\u0000send back their share and revoke the secret before a predefined date or event,\u0000i.e. so-called seal property. We also give two concrete constructions of\u0000CE-QSS-Seal (Collaboration-Encouraging Quantum Secret Sharing with Seal\u0000property) scheme. The first one is unconditional secure and achieve the optimal\u0000bound of a seal scheme. The second one improve the optimal bound of seal by\u0000introducing post-quantum secure computational assumption.","PeriodicalId":501226,"journal":{"name":"arXiv - PHYS - Quantum Physics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202255","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}
Emiliano Godinez-Ramirez, Richard Milbradt, Christian B. Mendl
{"title":"A Riemannian Approach to the Lindbladian Dynamics of a Locally Purified Tensor Network","authors":"Emiliano Godinez-Ramirez, Richard Milbradt, Christian B. Mendl","doi":"arxiv-2409.08127","DOIUrl":"https://doi.org/arxiv-2409.08127","url":null,"abstract":"Tensor networks offer a valuable framework for implementing Lindbladian\u0000dynamics in many-body open quantum systems with nearest-neighbor couplings. In\u0000particular, a tensor network ansatz known as the Locally Purified Density\u0000Operator employs the local purification of the density matrix to guarantee the\u0000positivity of the state at all times. Within this framework, the dissipative\u0000evolution utilizes the Trotter-Suzuki splitting, yielding a second-order\u0000approximation error. However, due to the Lindbladian dynamics' nature,\u0000employing higher-order schemes results in non-physical quantum channels. In\u0000this work, we leverage the gauge freedom inherent in the Kraus representation\u0000of quantum channels to improve the splitting error. To this end, we formulate\u0000an optimization problem on the Riemannian manifold of isometries and find a\u0000solution via the second-order trust-region algorithm. We validate our approach\u0000using two nearest-neighbor noise models and achieve an improvement of orders of\u0000magnitude compared to other positivity-preserving schemes. In addition, we\u0000demonstrate the usefulness of our method as a compression scheme, helping to\u0000control the exponential growth of computational resources, which thus far has\u0000limited the use of the locally purified ansatz.","PeriodicalId":501226,"journal":{"name":"arXiv - PHYS - Quantum Physics","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202223","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}
Alessandro Laneve, Michele B. Rota, Francesco Basso Basset, Mattia Beccaceci, Valerio Villari, Thomas Oberleitner, Yorick Reum, Tobias M. Krieger, Quirin Buchinger, Saimon F. Covre da Silva, Andreas Pfenning, Sandra Stroj, Sven Höfling, Armando Rastelli, Tobias Huber-Loyola, Rinaldo Trotta
{"title":"Wavevector-resolved polarization entanglement from radiative cascades","authors":"Alessandro Laneve, Michele B. Rota, Francesco Basso Basset, Mattia Beccaceci, Valerio Villari, Thomas Oberleitner, Yorick Reum, Tobias M. Krieger, Quirin Buchinger, Saimon F. Covre da Silva, Andreas Pfenning, Sandra Stroj, Sven Höfling, Armando Rastelli, Tobias Huber-Loyola, Rinaldo Trotta","doi":"arxiv-2409.07875","DOIUrl":"https://doi.org/arxiv-2409.07875","url":null,"abstract":"The generation of entangled photons from radiative cascades has enabled\u0000milestone experiments in quantum information science with several applications\u0000in photonic quantum technologies. Significant efforts are being devoted to\u0000pushing the performances of near-deterministic entangled-photon sources based\u0000on single quantum emitters often embedded in photonic cavities, so to boost the\u0000flux of photon pairs. The general postulate is that the emitter generates\u0000photons in a nearly maximally entangled state of polarization, ready for\u0000application purposes. Here, we demonstrate that this assumption is unjustified.\u0000We show that in radiative cascades there exists an interplay between photon\u0000polarization and emission wavevector, strongly affecting quantum correlations\u0000when emitters are embedded in micro-cavities. We discuss how the polarization\u0000entanglement of photon pairs from a biexciton-exciton cascade in quantum dots\u0000strongly depends on their propagation wavevector, and it can even vanish for\u0000large emission angles. Our experimental results, backed by theoretical\u0000modelling, yield a brand-new understanding of cascaded emission for various\u0000quantum emitters. In addition, our model provides quantitative guidelines for\u0000designing optical microcavities that retain both a high degree of entanglement\u0000and collection efficiency, moving the community one step further towards an\u0000ideal source of entangled photons for quantum technologies.","PeriodicalId":501226,"journal":{"name":"arXiv - PHYS - Quantum Physics","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202252","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}
E. Altuntas, R. G. Lena, S. Flannigan, A. J. Daley, I. B. Spielman
{"title":"Dynamical Structure Factor from Weak Measurements","authors":"E. Altuntas, R. G. Lena, S. Flannigan, A. J. Daley, I. B. Spielman","doi":"arxiv-2409.07030","DOIUrl":"https://doi.org/arxiv-2409.07030","url":null,"abstract":"Much of our knowledge of quantum systems is encapsulated in the expectation\u0000value of Hermitian operators, experimentally obtained by averaging projective\u0000measurements. However, dynamical properties are often described by products of\u0000operators evaluated at different times; such observables cannot be measured by\u0000individual projective measurements, which occur at a single time. For example,\u0000the dynamical structure factor describes the propagation of density\u0000excitations, such as phonons, and is derived from the spatial density operator\u0000evaluated at different times. Conventionally, this is measured by first\u0000exciting the system at a specific wavevector and frequency, then measuring the\u0000response. Here, we describe an alternative approach using a pair of\u0000time-separated weak measurements, and analytically show that their\u0000cross-correlation function directly recovers the dynamical structure factor. We\u0000provide numerical confirmation of this technique with a matrix product states\u0000simulation of the one-dimensional Bose-Hubbard model, weakly measured by phase\u0000contrast imaging. We explore the limits of the method and demonstrate its\u0000applicability to real experiments with limited imaging resolution.","PeriodicalId":501226,"journal":{"name":"arXiv - PHYS - Quantum Physics","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202304","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}
{"title":"Learning Robust Observable to Address Noise in Quantum Machine Learning","authors":"Bikram Khanal, Pablo Rivas","doi":"arxiv-2409.07632","DOIUrl":"https://doi.org/arxiv-2409.07632","url":null,"abstract":"Quantum Machine Learning (QML) has emerged as a promising field that combines\u0000the power of quantum computing with the principles of machine learning. One of\u0000the significant challenges in QML is dealing with noise in quantum systems,\u0000especially in the Noisy Intermediate-Scale Quantum (NISQ) era. Noise in quantum\u0000systems can introduce errors in quantum computations and degrade the\u0000performance of quantum algorithms. In this paper, we propose a framework for\u0000learning observables that are robust against noisy channels in quantum systems.\u0000We demonstrate that it is possible to learn observables that remain invariant\u0000under the effects of noise and show that this can be achieved through a\u0000machine-learning approach. We present a toy example using a Bell state under a\u0000depolarization channel to illustrate the concept of robust observables. We then\u0000describe a machine-learning framework for learning such observables across six\u0000two-qubit quantum circuits and five noisy channels. Our results show that it is\u0000possible to learn observables that are more robust to noise than conventional\u0000observables. We discuss the implications of this finding for quantum machine\u0000learning, including potential applications in enhancing the stability of QML\u0000models in noisy environments. By developing techniques for learning robust\u0000observables, we can improve the performance and reliability of quantum machine\u0000learning models in the presence of noise, contributing to the advancement of\u0000practical QML applications in the NISQ era.","PeriodicalId":501226,"journal":{"name":"arXiv - PHYS - Quantum Physics","volume":"58 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202261","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}
{"title":"Generalization Error Bound for Quantum Machine Learning in NISQ Era -- A Survey","authors":"Bikram Khanal, Pablo Rivas, Arun Sanjel, Korn Sooksatra, Ernesto Quevedo, Alejandro Rodriguez","doi":"arxiv-2409.07626","DOIUrl":"https://doi.org/arxiv-2409.07626","url":null,"abstract":"Despite the mounting anticipation for the quantum revolution, the success of\u0000Quantum Machine Learning (QML) in the Noisy Intermediate-Scale Quantum (NISQ)\u0000era hinges on a largely unexplored factor: the generalization error bound, a\u0000cornerstone of robust and reliable machine learning models. Current QML\u0000research, while exploring novel algorithms and applications extensively, is\u0000predominantly situated in the context of noise-free, ideal quantum computers.\u0000However, Quantum Circuit (QC) operations in NISQ-era devices are susceptible to\u0000various noise sources and errors. In this article, we conduct a Systematic\u0000Mapping Study (SMS) to explore the state-of-the-art generalization bound for\u0000supervised QML in NISQ-era and analyze the latest practices in the field. Our\u0000study systematically summarizes the existing computational platforms with\u0000quantum hardware, datasets, optimization techniques, and the common properties\u0000of the bounds found in the literature. We further present the performance\u0000accuracy of various approaches in classical benchmark datasets like the MNIST\u0000and IRIS datasets. The SMS also highlights the limitations and challenges in\u0000QML in the NISQ era and discusses future research directions to advance the\u0000field. Using a detailed Boolean operators query in five reliable indexers, we\u0000collected 544 papers and filtered them to a small set of 37 relevant articles.\u0000This filtration was done following the best practice of SMS with well-defined\u0000research questions and inclusion and exclusion criteria.","PeriodicalId":501226,"journal":{"name":"arXiv - PHYS - Quantum Physics","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202278","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}
Chen-Yu Liu, Chu-Hsuan Abraham Lin, Kuan-Cheng Chen
{"title":"Quantum-Train with Tensor Network Mapping Model and Distributed Circuit Ansatz","authors":"Chen-Yu Liu, Chu-Hsuan Abraham Lin, Kuan-Cheng Chen","doi":"arxiv-2409.06992","DOIUrl":"https://doi.org/arxiv-2409.06992","url":null,"abstract":"In the Quantum-Train (QT) framework, mapping quantum state measurements to\u0000classical neural network weights is a critical challenge that affects the\u0000scalability and efficiency of hybrid quantum-classical models. The traditional\u0000QT framework employs a multi-layer perceptron (MLP) for this task, but it\u0000struggles with scalability and interpretability. To address these issues, we\u0000propose replacing the MLP with a tensor network-based model and introducing a\u0000distributed circuit ansatz designed for large-scale quantum machine learning\u0000with multiple small quantum processing unit nodes. This approach enhances\u0000scalability, efficiently represents high-dimensional data, and maintains a\u0000compact model structure. Our enhanced QT framework retains the benefits of\u0000reduced parameter count and independence from quantum resources during\u0000inference. Experimental results on benchmark datasets demonstrate that the\u0000tensor network-based QT framework achieves competitive performance with\u0000improved efficiency and generalization, offering a practical solution for\u0000scalable hybrid quantum-classical machine learning.","PeriodicalId":501226,"journal":{"name":"arXiv - PHYS - Quantum Physics","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202311","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}
Avimita Chatterjee, Sonny Rappaport, Anish Giri, Sonika Johri, Timothy Proctor, David E. Bernal Neira, Pratik Sathe, Thomas Lubinski
{"title":"A Comprehensive Cross-Model Framework for Benchmarking the Performance of Quantum Hamiltonian Simulations","authors":"Avimita Chatterjee, Sonny Rappaport, Anish Giri, Sonika Johri, Timothy Proctor, David E. Bernal Neira, Pratik Sathe, Thomas Lubinski","doi":"arxiv-2409.06919","DOIUrl":"https://doi.org/arxiv-2409.06919","url":null,"abstract":"Quantum Hamiltonian simulation is one of the most promising applications of\u0000quantum computing and forms the basis for many quantum algorithms. Benchmarking\u0000them is an important gauge of progress in quantum computing technology. We\u0000present a methodology and software framework to evaluate various facets of the\u0000performance of gate-based quantum computers on Trotterized quantum Hamiltonian\u0000evolution. We propose three distinct modes for benchmarking: (i) comparing\u0000simulation on a real device to that on a noiseless classical simulator, (ii)\u0000comparing simulation on a real device with exact diagonalization results, and\u0000(iii) using scalable mirror circuit techniques to assess hardware performance\u0000in scenarios beyond classical simulation methods. We demonstrate this framework\u0000on five Hamiltonian models from the HamLib library: the Fermi and Bose-Hubbard\u0000models, the transverse field Ising model, the Heisenberg model, and the Max3SAT\u0000problem. Experiments were conducted using Qiskit's Aer simulator, BlueQubit's\u0000CPU cluster and GPU simulators, and IBM's quantum hardware. Our framework,\u0000extendable to other Hamiltonians, provides comprehensive performance profiles\u0000that reveal hardware and algorithmic limitations and measure both fidelity and\u0000execution times, identifying crossover points where quantum hardware\u0000outperforms CPU/GPU simulators.","PeriodicalId":501226,"journal":{"name":"arXiv - PHYS - Quantum Physics","volume":"45 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142202309","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}