Quantum Computers Measure Hall Viscosity of Fractional Quantum Hall State with Hilbert-Space Truncation
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The subtle behaviour of electrons in exotic states of matter holds the key to new technologies, and understanding their response to external forces is paramount. Ammar Kirmani from Los Alamos National Laboratory, Andrew A. Allocca from City College of the City University of New York, and Jian-Xin Zhu, also from Los Alamos National Laboratory, alongside Armin Rahmani from Western Washington University, Sriram Ganeshan and Pouyan Ghaemi from City College of the City University of New York, now present a method for measuring a property called Hall viscosity, a quantized response to changes in shape, within a complex quantum system.
This research overcomes a long-standing challenge in observing Hall viscosity in real materials, by instead simulating the behaviour of electrons using a quantum computer, offering a new pathway to explore these fundamental properties.
The team’s approach successfully predicts theoretical values within a limited system, demonstrating the potential of quantum computation to unlock insights into previously inaccessible states of matter and paving the way for future investigations into more complex quantum phenomena. Despite significant theoretical interest, directly observing this property in a physical FQH state has proven elusive, making it an ideal target for investigation using quantum computers. This work employs a quasi-one-dimensional model of an FQH state, coupled to a background geometry, to explore how the system responds to alterations in its shape, offering a new approach to understanding this subtle property of quantum matter and providing insights into the fundamental behaviour of FQH fluids.
This research also guides future experiments on both physical systems and quantum simulators.
Hall Viscosity Measured Via Quantum Circuitry Scientists engineered a quantum-circuit protocol to measure the Hall viscosity of a fractional quantum Hall (FQH) fluid, a challenging task for conventional experiments. The study utilized a quasi-one-dimensional model of an FQH state coupled to a background geometry, allowing researchers to investigate how the system responds to changes in shape. To realize this model, the team constructed circuits simulating a limited version of the system, enabling extraction of Hall viscosity from the evolution of the quantum state. Calculations were performed on IBM’s ibm marrakesh quantum computer, and the circuits were carefully mapped to the device using specialized software. To minimize errors and improve data quality, the team implemented sophisticated error-mitigation strategies, including techniques to suppress noise and enhance signal clarity, generating a large number of measurements for each circuit. Researchers carefully evaluated the system’s response on a cylinder with varying circumference, comparing results from quantum algorithms, quantum devices with and without error correction, and analytical calculations. This comparison demonstrated strong agreement between theory and experiment. While the current limitations of the model prevent accessing the fully quantized Hall viscosity, the hardware data aligns well with predictions within the restricted regime. Further refinement involved techniques to filter out noise, significantly reducing errors compared to calculations without this step. Despite limitations imposed by the finite cylindrical geometry of the quantum computation and the simplified model, the study successfully demonstrated the potential of quantum computing for simulating complex physical phenomena and performing measurements challenging for conventional methods.
The team’s results confirm that currently available quantum devices offer a powerful platform for exploring areas previously inaccessible to experimental investigation. Hall Viscosity and Orbital Spin Simulation This research investigates the fractional quantum Hall effect (FQHE), a fascinating phenomenon where two-dimensional electron systems exhibit quantized Hall conductance at fractional values, arising from strong electron-electron interactions and the formation of exotic quasiparticles. The study focuses on understanding geometric properties of the FQHE state, specifically Hall viscosity and orbital spin. Hall viscosity measures the internal rotation of the FQHE fluid, providing insights into its response to strain, while orbital spin describes the intrinsic angular momentum of the electrons.
The team utilized the Trugman-Kivelson model, an exactly solvable model capturing essential FQHE physics, to calculate these properties. The research combines analytical calculations with quantum simulations to accurately determine Hall viscosity and orbital spin. Analytical calculations provide a theoretical framework, while quantum simulations offer a complementary approach using quantum computers. By comparing results from analytical calculations, exact diagonalization, and quantum simulations, the researchers validated their findings and improved the accuracy of the quantum simulation results. The study provides analytical expressions for Hall viscosity and orbital spin within the Trugman-Kivelson model and demonstrates that quantum computers can accurately calculate these geometric properties. The validation process confirms the reliability of the quantum simulation results, and the use of extrapolation techniques further enhances their accuracy. This work contributes to a deeper understanding of the FQHE and its geometric properties, demonstrating the potential of quantum computers to simulate complex physical systems and advance materials science and topological quantum computation.
Laughlin Viscosity Measured on Quantum Computer Researchers have successfully measured the Hall viscosity of the Laughlin state, a fundamental property of fractional quantum Hall fluids, using a quantum computer. This achievement demonstrates the potential of quantum computing platforms to investigate complex physical phenomena challenging to study with conventional methods.
The team designed a quantum circuit based on a quasi-one-dimensional model of the Laughlin state, allowing them to extract the Hall viscosity from the dynamics of the simulated system. The hardware data obtained closely matched predictions from analytical calculations and numerical simulations, even within the limitations of the simplified model used in the quantum computation. While the current quantum hardware and model geometry prevent accessing the fully quantized value of Hall viscosity, the results confirm the feasibility of this approach. Future work will focus on refining the model and leveraging more powerful quantum computers to overcome these limitations and achieve a more precise measurement of the quantized Hall viscosity.
This research opens new avenues for exploring exotic states of matter and furthering our understanding of fundamental physics through the innovative application of quantum simulation techniques. 👉 More information 🗞 Measuring the Hall Viscosity of the Laughlin State on Noisy Quantum Computers 🧠 ArXiv: https://arxiv.org/abs/2512.09982 Tags: