Chang Li on LinkedIn: A quantum-entangled photon traveled 35 kilometers under the streets of… (2024)

Model robustness for feedback stabilization of open quantum systemsWeichao Liang& Nina Hadis Amini https://lnkd.in/eG8iBzRUQ-COAST ANR projet "Estimation and control of open quantum systems" : https://lnkd.in/e7G8fVKXAbstrat:This paper generalizes the results in [30] concerning feedback stabilization of target states for N-level quantum angular momentum systems undergoing quantum non-demolition measurements (QND) in absence of the knowledge about initial states and parameters. Here we consider multiple measurement operators and study the stabilization toward a chosen target subspace which is a common eigenspace of measurement operators. Under the QND conditions, we show that this analysis provides necessary tools to ensure feedback stabilization based on a simplified filter whose state is a N-dimensional vector. A numerical analysis has been proposed in [18]. This paper provides a complete proof for the use of a simplified filter in feedback stabilization. This has important practical use as the dimension of quantum systems is usually high. This paper opens the way toward a complete proof concerning the robustness of a stabilizing feedback with respect to approximate filters, which is lacking.

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Model robustness for feedback stabilization of open quantum systemshttps://lnkd.in/eG8iBzRUWeichao Liang, Nina Amini. Model robustness for feedback stabilization of open quantum systems.Automatica, In presshttps://lnkd.in/exDVzW4xhttps://lnkd.in/e7Dm5QP5Abstract:This paper builds upon and expands the findings presented in Liang etal. (2021). Our focus lies in scenarios where initial states and model parameters remain unknown. In contrast to prior research, we consider multiple measurement channels, addressing the challenge of global exponential stabilization towards a chosen target subspace. Under quantum non-demolition conditions, our analysis establishes essential tools for achieving feedback stabilization. Furthermore, we explore the utilization of a simplified filter as a viable alternative to full state estimator. While the effectiveness of this simplified filter was numerically examined in Cardona etal. (2020), our paper offers a comprehensive proof of its applicability in feedback stabilization. Furthermore, our analysis may serve as an inspiration for demonstrating the validation of the robust feedback stabilization through generic approximate filters.

https://lnkd.in/dqGa4FVkA New Quantum Advantage in Quantum Secret SharingOur result benchmarks the identification process of three qubit resources for task like secret sharing and teleportation while setting up large scale quantum network. #quantum #quantumtechnology

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I am very happy and proud for the work that Elisa Bäumer, PhD & co. have just published on the arxiv. This is really fine work and shows an important application of IBM Quantum Dynamic Circuits which allow mid circuits measurements and conditional feed-forward operations and in this case are used to create long-range entaglement. Looking forward to see what will come next! #quantumcomputing #qiskit

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The Future of Quantum - Developing a System Ready for QuantumCenter for Strategic & International Studies18 Jul 2023The United States must think strategically when contemplating how to position itself within the international quantum landscape. Research, development, and creation of a U.S. system to support quantum technology is critical to advancing quantum centric supercomputing. The National Quantum Initiative Act, which is set to be reauthorized in 2023, will guide the development of future policies and legislation to support the U.S. quantum industry.Join CSIS for a discussion on the importance of research, partnerships, and deployment of a quantum-ready system with Dr. Darío Gil, Senior Vice President and Director of Research at IBM.

Dissipation is a phenomenon that destroys quantum entanglement, a necessary resource in quantum algorithms. However, today we discuss how engineered dissipation can in fact aid a quantum processor by steering it into a desired entangled state → https://goo.gle/3UcpX1R

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Great reading material to start off your week! Here the topic is on the use of Dynamic Circuits for efficient long-range entanglement.#quantumcomputing #dynamiccircuits

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Quantum circuits with tunable-range interactions can probe a new dynamical transition in the propagation of correlations in quantum circuits. Discover more in PRX Quantum: https://go.aps.org/45CBkCU.

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New results on the time reversal of quantum and classical processes are obtained through a Bayesian framework, allowing one to identify cases that can be reversed without additional resources. Learn more in PRX Quantum: https://go.aps.org/3OS16gn.

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#Entanglement is a key resource in #quantuminformation and technologies. In excited many-body systems, entanglement increases during unitary dynamics, leading to highly entangled states. This contrasts with the area-law behavior of ground states. Over the past few years, it has been found that the interplay between local measurements and unitary dynamics in monitored quantum circuits results in a critical behavior where, at a certain measurement rate, a transition from volume- to area-law entanglement takes place. But, characterizing entanglement via quantum-state tomography is exponentially difficult with increasing subsystem size, which make experimental realization of entanglement phase transitions very challenging.In our recent study published in Phys Rev. Lett., we have proposed a scalable method to probe the entanglement dynamics and the measurement-induced phase transition. This approach is motivated by our earlier work were we conjectured a general connection between the scaling laws of entanglement entropies and variances of conserved extensive observables. Interestingly, measuring variances unlike quantum-state tomography, does not require a exponentially number of measurements in the subsystem size. These results may open new prospects to study the complex entanglement dynamics in existing and near-future #quantumcomputers.For more details please check out the following through ScienceCast.org:

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