Lu Group @ UNC Chapel Hill
Research
The vast majority of systems we interact with are far from thermal equilibrium, exhibiting highly complex behaviors in response to realistic and time-varying environments. A salient example is living organisms -- living organisms and abiotic systems, at the microscopic scale, follow the same underlying physical and chemical principles. However, through complex non-equilibrium processes coherently coupled across multiple scales, living organisms can achieve many more complex emergent functions than abiotic systems. In our theory group, we use tools from non-equilibrium statistical physics and advanced numerical methods to study the underlying principles behind the unique properties of non-equilibrium systems. Our research focuses on free energy transduction, information sensing and processing, and non-equilibrium manipulation for microscopic systems driven far from equilibrium. Understanding these processes allows us to obtain design principles for next-generation complex abiotic systems with life-like responsiveness.
Life-like Responsiveness in Complex Chemical Systems
Living organisms and abiotic systems follow the same underlying chemical and thermodynamic principles. However, distinct properties and structures emerge from living organisms via coherently coordinated non-equilibrium processes across multiple scales. We seek the theoretical understanding of how complex responsiveness emerges from living organisms and the design principles to design life-like abiotic systems with complex functional responsiveness.
Non-equilibrium Manipulation of Complex Systems
Non-equilibrium dynamics, despite being more challenging to analyze, can offer a broader range of controllability than quasi-static or steady-state dynamics. Our research group is specifically interested in manipulating complex non-equilibrium systems to achieve two types of control goals: first, to use non-equilibrium driving forces to enable molecules to reach states that are rarely accessible at equilibrium; and second, to design non-equilibrium shortcuts that can steer a system into a desired state without involving slow dynamics.
Information Sensing and Transduction at the Molecular Scale
Living cells use molecular sensors to detect and transmit information about their environments. Our research group employs various levels of stochastic thermodynamics models to address important questions related to biological sensors, such as: Do sensors only sense one type of information, or can they simultaneously detect multiple types of information? Are there trade-offs between a sensor's accuracy and response speed? How can we visualize and design the microscopic information flow through a macromolecule? Can a smart molecular complex perform information processing or computing?
Mathematical and Geometrical Origins of Thermodynamics
Thermodynamics theory, ultimately, is an emergent theory that does not rely on the underlying physical and chemical details. In collaboration with Prof. Hong Qian from UW Seattle, we have gained more understanding of the mathematical and geometrical origin of thermodynamics and phase transitions. To learn more about other research projects in this area, please don't hesitate to contact us.
Theoretical Tools and Approaches
Our research utilizes physical insights to simplify complex non-equilibrium processes into clean and general toy models. We analyze these models using numerical simulation and, most importantly, theoretical tools such as stochastic thermodynamics, information science, probability theory, graph theory, large deviation theory, and occasionally topology, to derive general physical laws.
Our Team
Chase Slowey
Ph.D. Candidate (Physical Chemistry)
Department of Chemistry
Joined since 2019
Supraja Chittari
Ph.D. Candidate (Physical Chemistry)
Department of Chemistry
Joined the group since 2020
Joint student with Knight's Group
Asawari Pagare
Ph.D. Candidate (Physical Chemistry)
Department of Chemistry
Joined since 2020
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Ziheng Guo
Undergraduate Researcher
Department of Chemistry
2022- 2024
Currently at Johns Hopkins University
Sa Hoon Min
Postdoctoral Scholar
Department of Chemistry
2020 to 2022
Zhongmin Zhang
Postdoctoral Scholar
Department of Chemistry
Since 2020
Vincent Du
Ph.D. Student (Physical Chemistry)
Department of Chemistry
Joined the group since 2022
Our Philosophy
Non-equilibrium theory, despite its potential, remains underutilized in our understanding of complex chemical and biological processes. This gap is evidenced by the persistence of counter-intuitive phenomena, such as the Mpemba effect, catalytic oscillations that invert reaction directions, and even the withdrawal effect. Our research philosophy is rooted in the belief that these surprises are not mere anomalies, but rather signposts pointing to the limitations of our current intuitions and theories. When confronted with a counter-intuitive effect, we first acknowledge that our intuition must be flawed—either due to outdated theories or hidden, inapplicable assumptions. Our mission then becomes twofold: to identify these flawed intuitions and to forge a path toward updating them. In this process, we strive to develop minimal models that capture the essence of the underlying physics. This approach leads us to either formulate new theories for the systems of interest or uncover and revise hidden assumptions that have shaped our outdated intuitions. Ultimately, our goal is to transform these once-surprising effects into logical outcomes of our updated understanding, aligning our expectations with reality. Through this process, we not only resolve individual puzzles but also advance the broader application of non-equilibrium theory in chemistry and biology.
Publications
Peer-reviewed Papers as PI at UNC-Chapel Hill
Preprints / under review:
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Z. Zhang, Z. Lu, "Single-molecule Automata: Harnessing Kinetic-Thermodynamic Discrepancy for Temporal Pattern Recognition", arXiv:2409.19803 (2024)
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A. Pagare, Z. Lu, "Information Benchmark for Biological Sensors Beyond Steady States -- Mpemba-like sensory withdrawal effect", arXiv:2406.04304 (2024)
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J. Zheng, Z. Lu, "Information Geometry and Universal Bounds on Non-stationary Responsiveness of Markov Dynamics", arXiv:2403.10952 (2024)
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Y-C. Cheng, W. Wang, Z. Lu, H. Qian, "Generalized Boltzmann distributions for systems strongly coupled to large finite bath -- a microcanonical approach", arXiv:1811.11321v5 (2021)
Published papers as PI at UNC-Chapel Hill:
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Chittari, Supraja S., and Z. Lu, "Revisiting Kinetic Monte Carlo Algorithms for Time-dependent Processes: from open-loop control to feedback control", Journal of Chemical Physics, J. Chem. Phys. 161 (2024): 044104.
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A. Pagare, Z. Zhang, J. Zheng, Z. Lu, "Stochastic Distinguishability of Markovian Trajectories", Journal of Chemical Physics, 160 (2024): 171101.
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Z. Zhang, Z. Lu, "Non-equilibrium Theoretical Framework and Universal Design Principles of Oscillation-Driven Catalysis", Journal of Physical Chemistry Letters, 14 (2023): 7541. (Cover)
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Chittari, Supraja S., and Z. Lu. "Geometric approach to nonequilibrium hasty shortcuts", Journal of Chemical Physics, 159 (2023): 084106.
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A. Pagare, SH. Min, Z. Lu. "Theoretical upper bound of multiplexing in biological sensory receptors" Physical Review Research, 5 (2023): 023032.
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Z. Zhang, V. Du, Z. Lu. "Energy landscape design principle for optimal energy harnessing by catalytic molecular machines." Physical Review E 107 (2023): L012102. (access for free at arXiv:2205.11647)
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C. Slowey, Z. Lu. "Sloppy gear mechanism for coupled stochastic transportation: From antiequilibrium flow to kinetic selectivity." Physical Review Research 4 (2022): 023234.
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Z. Lu, H. Qian. "Emergence and Breaking of Duality Symmetry in Generalized Fundamental Thermodynamic Relations." Phys. Rev. Lett. 128, (2022): 150603. (access for free at arXiv:2009.12644)
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Papers before Joining UNC
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X. Gao, Y. Jiang, Y. Lin, K.H. Kim, Y. Fang, J. Yi, L. Meng, H.C. Lee, Z. Lu, O. Leddy, R. Zhang, Q. Tu, W. Feng, V. Nair, P. Griffin, F. Shi, G. Shekhawat, A. Dinner, H.G. Park, B.Tian."Structured silicon for revealing transient and integrated signal transductions in microbial systems." Science Advances 6, no. 7 (2020): eaay2760.
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Z. Lu*†, C. Jarzynski*†. "A Programmable Mechanical Maxwell’s Demon." Entropy 21, no. 1 (2019): 65.
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W. Zhong, Z. Lu, D. Schwab, A. Murugan. "Nonequilibrium Statistical Mechanics of Continuous Attractors." Neural Computation 32, no. 6 (2020): 1033-1068.
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O. Leddy*, Z. Lu*, A. R. Dinner. "Entropic constraints on the steady-state fitness of competing self-replicators." The Journal of chemical physics 149, no. 22 (2018): 224105.
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W. Pittayakanchit*, Z. Lu*, J. Chew, M. J. Rust, A. Murugan. "Biophysical clocks face a trade-off between internal and external noise resistance." Elife 7 (2018): e37624.
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Z. Lu*†, O. Raz*†, "Nonequilibrium thermodynamics of the Markovian Mpemba effect and its inverse." Proceedings of the National Academy of Sciences 114, no. 20 (2017): 5083-5088.
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C. Xu, N. Zheng†, L P. Wang, L. Li†, Q. Shi, Z. Lu†. "Self-propulsion of a grain-filled dimer in a vertically vibrated channel." Scientific Reports 7, no. 1 (2017): 1-11.
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Z. Lu, D. Mandal, C. Jarzynski, "Engineering Maxwell’s demon." Physics Today 67, no. 8 (2014): 60-61.
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F. Liu, H. Xie, Z. Lu, "Generalized integral fluctuation relation with feedback control for diffusion processes." Communications in Theoretical Physics, 62(4), p.571.
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*equal authors †co-corresponding authors.
Our Recent Posters
News
2024
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Congratulations to Zhongmin Zhang for winning the JCP Best Poster award at the triennial ACTC 2024 conference.
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We are hosting the ACTC 2024 conference at Chapel Hill, NC.
2023
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Congratulations to Zhongmin's paper "Non-equilibrium Theoretical Framework and Universal Design Principles of Oscillation-Driven Catalysis" highlighted on the Cover of Journal of Physical Chemistry Letters.
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Congratulations to Asawari and Sa Hoon for the paper "Theoretical upper bound of multiplexing in biological sensory receptors" to appear at Physical Review Research.
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Congratulations to Zhongmin and Vincent for publishing the new geometrical design principle of energy harvesting catalytic molecular machines on Phys. Rev. E.
2022
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Can hot water freeze faster than cold water? Check out the news article in Quanta Magazine.
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Congratulations to Chase Slowey for publishing his anti-equilibrium transportation on Phys. Rev. Research.
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Our research with Collaborator Prof. Hong Qian on the duality symmetry in thermodynamic relations gets published at Phys. Rev. Lett.
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We appreciate the NSF for the NSF CAREER AWARD support between 2022 and 2027.
2021
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The list of speakers for the Spring 2021 Physical Chemistry Seminar at UNC-Chapel Hill is announced! Join us via Zoom.
2020
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Congratulations to Chase Slowey for winning the Poster Contest and the Cash Prize at the NC ACS Local Meeting. (Nov. 23, 2020)