publications

preprints

Unpublished

1. arXiv

   Reservoir-Engineered Exceptional Points for Quantum Energy Storage

   Borhan Ahmadi, André H. A. Malavazi, Paweł Mazurek, and 2 more authors

   2025

   Bib

   @unpublished{ahmadi2025reservoir,
     title = {Reservoir-Engineered Exceptional Points for Quantum Energy Storage},
     author = {Ahmadi, Borhan and Malavazi, Andr{\'e} H. A. and Mazurek, Pawe{\l} and Horodecki, Pawe{\l} and Barzanjeh, Shabir},
     journal = {arXiv:2511.20569},
     year = {2025},
     url = {https://arxiv.org/abs/2511.20569}
   }

conference & journal articles

Journal Articles

1. PRX Energy

   Charge-preserving operations in quantum batteries

   André H. A. Malavazi, Borhan Ahmadi, Paweł Horodecki, and 1 more author

   PRX Energy, Mar 2026

   DOI Bib

   @article{malavazi2025charge,
     title = {Charge-preserving operations in quantum batteries},
     author = {Malavazi, André H. A. and Ahmadi, Borhan and Horodecki, Paweł and Dieguez, Pedro R.},
     journal = {PRX Energy},
     pages = {--},
     year = {2026},
     month = mar,
     publisher = {American Physical Society},
     doi = {10.1103/2jtp-jpkn},
     url = {https://link.aps.org/doi/10.1103/2jtp-jpkn},
     scholar_id = {},
     article_id = {},
     dimensions = {true},
   }

2. EPJ PLus

   Fluctuation theorems with optical tweezers: theory and practice

   Thalyta T Martins, André H. A. Malavazi, Lucas P Kamizaki, and 4 more authors

   The European Physical Journal Plus, Mar 2026

   Abs DOI Bib

   Fluctuation theorems, such as the Jarzynski equality and the Crooks relation, are effective tools connecting non-equilibrium work statistics and equilibrium free energy differences. However, detailed hands-on, reproducible protocols for implementing and analyzing these relations in real experiments remain scarce. This tutorial provides an end-to-end workflow for measuring, validating, and applying fluctuation theorems using a single-beam optical tweezers setup. It introduces the foundational ideas and consolidates practical calibration (PSD-based trap stiffness and position sensitivity), protocol design (forward/reverse finite-time drives over multiple amplitudes and durations), and robust estimators for free energy difference and dissipated work, highlighting finite sampling and rare event effects. We demonstrate the procedures using an extensive set of measured trajectories under different conditions and provide openly accessible datasets and Python code, enabling new researchers or educators to reproduce the results with minimal effort. Beyond pedagogical validation, we discuss how these recipes translate to broader soft-matter and mesoscopic contexts. By combining user-friendly instruments with clear and transparent analysis, this work promotes the education and reliable adoption of stochastic thermodynamic methods in the curricula of physics and chemistry, as well as among emerging research teams.

   @article{martins2026fluctuation,
     doi = {https://doi.org/10.1140/epjp/s13360-025-07181-4},
     url = {https://link.springer.com/article/10.1140/epjp/s13360-025-07181-4},
     title = {Fluctuation theorems with optical tweezers: theory and practice},
     author = {Martins, Thalyta T and Malavazi, André H. A. and Kamizaki, Lucas P and Petrosyan, Artyom and Besga, Benjamin and Ciliberto, Sergio and Muniz, S{\'e}rgio R},
     journal = {The European Physical Journal Plus},
     volume = {141},
     number = {1},
     pages = {71},
     year = {2026},
     publisher = {Springer},
     scholar_id = {pN5CdqEAAAAJ},
     article_id = {hqOjcs7Dif8C},
     dimensions = {true},
   }

3. J. Phys.: Conf. Ser.

   Revival and instabilities of entanglement in monitoring maps with indefinite causal order

   Shahana Aziz, André H. A. Malavazi, and Pedro R. Dieguez

   Journal of Physics: Conference Series, Jun 2025

   Abs DOI Bib

   In this proceeding, we revisit the discussion presented in Ref. [Commun Phys 7, 373 (2024)], which examines the behavior of a quantum switch involving two arbitrary quantum operations when the control is exposed to environmental effects. Our study extends this analysis by focusing on the evolution of entanglement in the target system within the quantum switch framework, taking into account the influence of environmental conditions and control post-selection. We find that entanglement evolution is highly sensitive to these factors. While entanglement sudden death occurs under definite causal order, indefinite causal order can reverse this loss. We observe entanglement revival in high-temperature regimes and a sudden reappearance of entanglement under weak monitoring conditions at low temperatures. These findings provide insights into the resilience of the quantum switch in the presence of environmental disturbances and highlight its potential for applications where preserving entanglement is essential.

   @article{Aziz_2025,
     doi = {10.1088/1742-6596/3017/1/012044},
     url = {https://dx.doi.org/10.1088/1742-6596/3017/1/012044},
     year = {2025},
     month = jun,
     publisher = {IOP Publishing},
     volume = {3017},
     number = {1},
     pages = {012044},
     author = {Aziz, Shahana and Malavazi, André H. A. and Dieguez, Pedro R.},
     title = {Revival and instabilities of entanglement in monitoring maps with indefinite causal order},
     journal = {Journal of Physics: Conference Series},
     dimensions = {true},
   }

4. PRX Energy

   Two-time weak measurement protocol for ergotropy protection in open quantum batteries

   André H. A. Malavazi, Rishav Sagar, Borhan Ahmadi, and 1 more author

   PRX Energy, May 2025

   Abs DOI Bib

   Quantum batteries are emerging as highly efficient energy storage devices that can exceed classical performance limits. Although there have been significant advancements in controlling these systems, challenges remain in stabilizing stored energy and minimizing losses due to inevitable environmental interaction. In this paper, we propose a protocol that employs selective weak measurements to protect quantum states from such influence and mitigate battery discharging, that is feasible in state-of-the-art technologies. We establish thermodynamic constraints that allow this method to be implemented without disrupting the overall energy and ergotropy balance of the system, i.e., with no extra net recharging. Our findings demonstrate that appropriately chosen measurement intensity can reduce unwanted discharging effects, thereby preserving ergotropy and improving the stability of quantum batteries. We illustrate the protocol with single and two-qubit systems and establish the generalization for N-cell batteries. Additionally, we explore how weak measurements influence the coherent and incoherent components of ergotropy, providing new insights into the practical application of quantum coherence in energy storage technologies.

   @article{bv4w-jr6q,
     title = {Two-time weak measurement protocol for ergotropy protection in open quantum batteries},
     author = {Malavazi, Andr\'e H. A. and Sagar, Rishav and Ahmadi, Borhan and Dieguez, Pedro R.},
     journal = {PRX Energy},
     pages = {--},
     year = {2025},
     month = may,
     publisher = {American Physical Society},
     doi = {10.1103/bv4w-jr6q},
     url = {https://link.aps.org/doi/10.1103/bv4w-jr6q},
     dimensions = {true},
   }

5. Comm. Phys.

   Quantum switch instabilities with an open control

   Otavio A. D. Molitor, André H. A. Malavazi, Roberto Dobal Baldijão, and 3 more authors

   Communications Physics, Nov 2024

   Abs DOI Bib

   The superposition of causal orders shows promise in various quantum technologies. However, the fragility of quantum systems arising from environmental interactions, leading to dissipative behavior and irreversibility, demands a deeper understanding of the possible instabilities in the coherent control of causal orders. In this work, we employ a collisional model to investigate the impact of an open control system on the generation of interference between two causal orders. We present the environmental instabilities for the switch of two arbitrary quantum operations and examine the influence of environmental temperature on each potential outcome of control post-selection. Additionally, we explore how environmental instabilities affect protocol performance, including switching between mutually unbiased measurement observables and refrigeration powered by causal order superposition, providing insights into broader implications.

   @article{Molitor2024,
     author = {Molitor, Otavio A. D. and Malavazi, Andr{\'e} H. A. and Baldij{\~a}o, Roberto Dobal and Orthey, Alexandre C. and Paiva, Ismael L. and Dieguez, Pedro R.},
     title = {Quantum switch instabilities with an open control},
     journal = {Communications Physics},
     year = {2024},
     month = nov,
     day = {19},
     volume = {7},
     number = {1},
     pages = {373},
     issn = {2399-3650},
     doi = {10.1038/s42005-024-01843-y},
     url = {https://doi.org/10.1038/s42005-024-01843-y},
     dimensions = {true},
   }

6. PRE

   Detuning effects for heat-current control in quantum thermal devices

   André H. A. Malavazi, Borhan Ahmadi, Paweł Mazurek, and 1 more author

   Phys. Rev. E, Jun 2024

   Abs DOI Bib

   Navigating the intricacies of thermal management at the quantum scale is a challenge in the pursuit of advanced nanoscale technologies. To this extent, theoretical frameworks introducing minimal models mirroring the functionality of electronic current amplifiers and transistors, for instance, have been proposed. Different architectures of the subsystems composing a quantum thermal device can be considered, tacitly bringing drawbacks or advantages if properly engineered. This paper extends the prior research on thermotronics, studying a strongly coupled three-subsystem thermal device with a specific emphasis on a third excited level in the control subsystem. Our setup can be employed as a multipurpose device conditioned on the specific choice of internal parameters: heat switch, rectifier, stabilizer, and amplifier. The exploration of the detuned levels unveils a key role in the performance and working regime of the device. We observe a stable and strong amplification effect persisting over broad ranges of temperature. We conclude that considering a three-level system, as the one directly in contact with the control temperature, boosts output currents and the ability to operate our devices as a switch at various temperatures.

   @article{PhysRevE.109.064146,
     title = {Detuning effects for heat-current control in quantum thermal devices},
     author = {Malavazi, Andr\'e H. A. and Ahmadi, Borhan and Mazurek, Pawe\l{} and Mandarino, Antonio},
     journal = {Phys. Rev. E},
     volume = {109},
     issue = {6},
     pages = {064146},
     numpages = {16},
     year = {2024},
     month = jun,
     dimensions = {true},
     publisher = {American Physical Society},
     doi = {10.1103/PhysRevE.109.064146},
     url = {https://link.aps.org/doi/10.1103/PhysRevE.109.064146}
   }

7. Entropy

   A Schmidt decomposition approach to quantum thermodynamics

   André H. A. Malavazi and Frederico Brito

   Entropy, Jun 2022

   Abs DOI Bib

   The development of a self-consistent thermodynamic theory of quantum systems is of fundamental importance for modern physics. Still, despite its essential role in quantum science and technology, there is no unifying formalism for characterizing the thermodynamics within general autonomous quantum systems, and many fundamental open questions remain unanswered. Along these lines, most current efforts and approaches restrict the analysis to particular scenarios of approximative descriptions and semi-classical regimes. Here, we propose a novel approach to describe the thermodynamics of arbitrary bipartite autonomous quantum systems based on the well-known Schmidt decomposition. This formalism provides a simple, exact, and symmetrical framework for expressing the energetics between interacting systems, including scenarios beyond the standard description regimes, such as strong coupling. We show that this procedure allows straightforward identification of local effective operators suitable for characterizing the physical local internal energies. We also demonstrate that these quantities naturally satisfy the usual thermodynamic notion of energy additivity.

   @article{malavazi2022schmidt,
     title = {A Schmidt decomposition approach to quantum thermodynamics},
     author = {Malavazi, Andr{\'e} H. A. and Brito, Frederico},
     journal = {Entropy},
     volume = {24},
     number = {11},
     pages = {1645},
     year = {2022},
     publisher = {MDPI},
     dimensions = {true},
     doi = {10.3390/e24111645},
     url = {https://doi.org/10.3390/e24111645}
   }

Ph.D. thesis

Journal Articles

1. Ph.D. Thesis

   On the energetic analysis of autonomous quantum systems

   André H. A. Malavazi

   2022

   Bib

   @article{hernandes2022energetic,
     title = {On the energetic analysis of autonomous quantum systems},
     author = {Malavazi, Andr{\'e} H. A.},
     journal = {},
     year = {2022}
   }