A pleasure to visit the @yonsei_u physics department and to give a colloquium on #OpenQuantumSystems for "Precision Thermometry at the Extremes". Great opportunity to report on our recent progress in constructing optimal observables from the master equation. #QuantumMetrology

NITheCS & QSUN Seminar: ‘High-temperature limit penalising high-frequency quantum fluctuations’ - Dr Graeme Pleasance (SU) 📅 Fri, 7 August 🕑 14h00-15h00 SAST 📍 Attend in person or online 🔗 buff.ly/Xgpqvjb #QuantumBrownianMotion #OpenQuantumSystems #QuantumDecoherence

NITheCS & UKZN Seminar: Universality & Scaling in Open Quantum Systems under Cooling Dynamics. 👤 Prof Michael Kastner 📅 Tues, 21 April ⏰ 14:10 SAST Attend online or in person buff.ly/DOR4VXi #QuantumPhysics #OpenQuantumSystems #QuantumCriticality #NonequilibriumPhysics

🚨 Time update! NITheCS & QSUN Seminar: 'Efficient pseudomode mapping for strongly coupled open quantum systems', by Dr Graeme Pleasance. 🗓 Fri, 10 Apr ⏰ 13h00–14h00 SAST (updated time) 📍 Attend in person or online buff.ly/IXfP2xQ #QuantumPhysics #OpenQuantumSystems

We revisit the Caldeira–Leggett model of quantum Brownian motion and uncover a new high-temperature limit that penalizes high-frequency quantum fluctuations. Our result yields a guaranteed Lindblad-form master equation. arxiv.org/abs/2508.14262 #QuantumPhysics #OpenQuantumSystems #Decoherence #QuantumThermodynamics

Dissipative time crystals are many-body #openquantumsystems that exhibit non-trivial time periodic motion at late times. We examine the onset and resilience of such emergent time periodicity in a few-body all-to-all interacting Lipkin-Meshkov-Glick model, where one of the constituents is locally in contact with a thermal bath. Employing both a #collisionmodel framework and a suitable time-continuous description, we show that stable time-crystalline behavior can only be exhibited when the bath acts as purely dissipative channel. We assess the role that the microscopic interactions within the system play, establishing that for the all-to-all model the introduction of temperature leads to a melting of the dissipative #timecrystallinity, in contrast to stable long-time periodicity which can be maintained for nearest neighbor XXZ type interactions.

Feedback control of #openquantumsystems is of fundamental importance for practical applications in various contexts, ranging from #quantumcomputation to quantum error correction and quantum metrology. Its use in the context of #thermodynamics further enables the study of the interplay between information and energy. However, deriving optimal #feedback control strategies is highly challenging, as it involves the optimal control of open quantum systems, the stochastic nature of quantum #measurement, and the inclusion of policies that maximize a long-term time- and trajectory-averaged goal. In this work, we employ a #reinforcementlearning approach in #machinelearning to automate and capture the role of a quantum @Maxwell's demon: the #agent takes the literal role of discovering optimal feedback control strategies in qubit-based systems that maximize a trade-off between measurement-powered cooling and measurement efficiency. Considering weak or projective quantum measurements, we explore different regimes based on the ordering between the thermalization, the measurement, and the unitary feedback timescales, finding different and highly non-intuitive, yet interpretable, strategies. In the thermalization-dominated regime, we find strategies with elaborate finite-time thermalization protocols conditioned on measurement outcomes. In the measurement-dominated regime, we find that optimal strategies involve adaptively measuring different qubit observables reflecting the acquired information, and repeating multiple weak measurements until the quantum state is "sufficiently pure", leading to random walks in state space. Finally, we study the case when all timescales are comparable, finding new feedback control strategies that considerably outperform more intuitive ones. We discuss a two-qubit example where we explore the role of entanglement and conclude discussing the scaling of our results to quantum many-body systems.

#topcitedpaper: "Entanglement Robustness via Spatial Deformation of Identical Particle Wave Functions", by Matteo Piccolini et al. mdpi.com/1099-4300/23/6/708 #openquantumsystems

New #SpecialIssue "Dynamics of Open Quantum Systems: Quantum Fluctuations, Decoherence and Emergent Phenomena", edited by Dr. Fernando C. Lombardo and Dr. Paula I. Villar, is open for submission! mdpi.com/journal/entropy/spe… #openquantumsystems #decoherence #quantumfluctuations

#mdpientropy Quantum Non-Markovian Environment-to-System Backflows of Information: Nonoperational vs. Operational Approaches mdpi.com/1099-4300/24/5/649 #openquantumsystems #quantum #nonMarkovianity

#mdpientropy "Non-Markovian Quantum Dynamics in a Squeezed Reservoir" mdpi.com/1099-4300/24/3/352 #openquantumsystems #squeezedstates #nonMarkoviandynamics

#OpenQuantumSystems, where system-environment couplings are periodically modulated, are studied, and formalism is developed to apply optimal control and machine learning techniques to quantum thermal machines. @UninaIT @INFN_ @UniGenova go.aps.org/3swsdSb

#mdpientropy "Stochastic Collisional Quantum Thermometry" mdpi.com/1099-4300/23/12/163… #openquantumsystems #quantumthermometry #collisionmodels

A framework for resource-efficient characterization and control of non-Markovian #OpenQuantumSystems is developed based on the notion of frames, overcoming severe constraints of existing approaches. @Griffith_Uni @dartmouth go.aps.org/3zVsssr

#mdpientropy "Memory Effects in Quantum Dynamics Modelled by Quantum Renewal Processes" mdpi.com/1099-4300/23/7/905 #openquantumsystems #renewalprocesses #memoryeffects #masterequations

"Quantum Stochastic Neural Maps and Quantum Neural Networks" papers.ssrn.com/sol3/papers.… #QuantumNeuralNetworks #OpenQuantumSystems #AI #ArtificialIntelligence #QuantumAI #QuantumComplexity #ComplexQuantumSystems #QuantumFractals #ChaosTheory #QuantumChaos

I really hope it will be the first of a long series on #openquantumsystems in the #earlyuniverse! (8/8)

An international team of researchers, led by scientists from IFISC (UIB-CSIC), propose a new approach to Markovian #OpenQuantumSystems from statistical physics theory and collisional models. ℹ : ifisc.uib-csic.es/en/news/if…

New #SpecialIssue "Open Quantum Systems", edited by Prof. David Zueco and Dr. Aurelia Chenu, with deadline 30 September 2021. We look forward to your submissions! mdpi.com/journal/entropy/spe… #OpenQuantumSystems #QuantumTechnologies

For the last 4 years I have primarily sticked with Wolfram Mathematica and packages therein. But seems like community is not very strong/popular. Learning QuTip for Python now, which seems very rich with a large supportive community. #QuTip #quantummodeling #openquantumsystems