Speaker: Alessandro Candeloro (University of Milan, ITA) When: Wednesday, 8th September 2021, 3PM (CET time) Where: online (Zoom) zoom.us/my/aula.polvani
Title: Properties of the asymptotic incompatibility measure in multiparameter quantum estimation
Abstract: We address the use of asymptotic incompatibility (AI) to assess the quantumness of a multiparameter quantum statistical model. AI is a recently introduced measure which quantifies the difference between the Holevo and the SLD scalar bounds, and can be evaluated using only the symmetric logarithmic derivative (SLD) operators of the model. At first, we evaluate analytically the AI of the most general quantum statistical models involving two-level (qubit) and single-mode Gaussian continuous-variable quantum systems, and prove that AI is a simple monotonous function of the state purity. Then…. (attend the seminar to know the rest)
REFERENCES Alessandro Candeloro, Matteo G. A. Paris, Marco G. Genoni On the properties of the asymptotic incompatibility measure in multiparameter quantum estimation arXiv:2107.13426
Speaker: Alessandro Candeloro (University of Milan, ITA) When: Tuesday, 4th May 2021, 2:30PM (CET time) Where: online (Zoom) zoom.us/my/aula.x
Title: Measurement-powered engine
Abstract: In the quantum realm, irreversibility primarily comes from the measurement process. From a thermodynamical point of view, the latter plays a role similar to a hot source with the noticeable difference that, in this case, the fuel is not thermal but quantum. In this seminar, the concept of a measurement-fueled engine based on a single qubit will be introduced, revealing the energetic counterpart of measurement devices. Then, the measurement process will be described from a quantum perspective, considering the creation of quantum correlations between the system to measure and a quantum meter. Energy and entropy flow along this process will be studied, unveiling the microscopic origin of the measurement fuel, and proving that entanglement plays a crucial role in the fueling mechanism. These can be regarded as a new class of heat engines in which there is no thermal bath, and the only source of fuel and noise is the measurement itself.
Heng-Ji Li from the School of Computer Science of the Beijing University of Posts and Telecommunications is going to join our group as a visiting scholar starting from April 2021. Welcome on board Heng-Ji!
He is going to deliver our group seminar. See the details here below.
Speaker: Heng-Ji Li (Beijing University of Posts and Telecommunications, CHN) When: Wednesday, 7thh Aprile 2021, 3PM (CET time) Where: online (Zoom) zoom.us/my/aula.consiglio
Title: Accomplishing quantum information tasks with coined quantum walks
Abstract: Quantum walks (QWs) have received much attention due to their many potential applications for quantum information processing in recent years. In our work, we take advantage of the properties of coined quantum walks to accomplish some quantum information tasks, such as quantum teleportation, quantum information splitting and quantum teleportation of shared quantum secret. To do it, different kinds of models of QWs are used, such as QWs with multiple walkers, coins and so on. This work opened wider application of QWs and provided inspiration to explore the potential applications of QWs.
Speaker: Abolfazl Bayat (University of Electronic Science and Technology of China, CHN) When: Thursday, 14th January 2020, 3PM (CET time) Where: online (Zoom) zoom.us/my/aula.x
Title: Driving enhanced quantum sensing in partially accessible many-body systems
Abstract: Ground state criticality of many-body systems is a resource for quantum enhanced sensing, namely Heisenberg precision limit, provided that one has access to the whole system. We show that for partial accessibility the sensing capacity of a block in the ground state reduces to sub-Heisenberg limit. To compensate for this, we drive the system periodically and use the local steady state for quantum sensing. Remarkably, the steady state sensing shows a significant enhancement in its precision in comparison with the ground state and even shows super-Heisenberg scaling for a certain range of frequencies. The origin of this precision enhancement is found to be the closing of the Floquet gap. This is in close correspondence with the role of the vanishing energy gap at criticality for quantum enhanced ground state sensing with global accessibility.
Speaker: Jan Chwedenczuk (Warsaw University, POL) When: Thursday, 7th January 2020, 3PM (CET time) Where: online (Zoom) zoom.us/my/aula.x
Title: Many-body nonlocality as a resource for quantum-enhanced metrology
Abstract: In this talk I will argue that the strongest quantum correlation, manifested by a many-body nonlocality, is a resource for ultra-precise metrology. I will show that the sensitivity of a quantum sensor can be expressed in terms of many-body correlation functions (such that witness the nonlocality) of all orders. I will illustrate this general result with some prominent examples, such as a collection of spins forming an Ising chain or a gas of ultra-cold bosons in any two-mode configuration.
We are also glad to announce one more seminar [ more details in the next weeks — SAVE THE DATE(S) ]
Speaker: Abolfazl Bayat (University of Electronic Science and Technology of China Chengdu, CHN) When: Thursday, 14th January 2020, 3PM (CET time) Where: online (Zoom) zoom.us/my/aula.x Title: TBA
Quantum Technology Lab – Dipartimento di Fisica – Università degli Studi di Milano