The phase diagram of quantum chromodynamics in one dimension on a quantum computer

Than, Anton T. [University of Maryland, College Park, MD (United States)]; Atas, Yasar Y. [University of Waterloo, ON (Canada)] (ORCID:0000000275855973); Chakraborty, Abhijit [University of Waterloo, ON (Canada)] (ORCID:0000000174879925); Zhang, Jinglei [University of Waterloo, ON (Canada)] (ORCID:0000000231007921); Diaz, Matthew T. [University of Maryland, College Park, MD (United States)]; Wen, Kalea [University of Maryland, College Park, MD (United States); College of William and Mary, Williamsburg, VA (United States)] (ORCID:0009000075349504); Liu, Xingxin [University of Maryland, College Park, MD (United States)] (ORCID:0009000573278470); Lewis, Randy [York University, Toronto, ON (Canada)] (ORCID:0009000548697155); Green, Alaina M. [University of Maryland, College Park, MD (United States)] (ORCID:0000000333654433); Muschik, Christine A. [University of Waterloo, ON (Canada); Perimeter Institute for Theoretical Physics, Waterloo, ON (Canada)] (ORCID:0000000245995107); Linke, Norbert M. [University of Maryland, College Park, MD (United States); Duke University, Durham, NC (United States)] (ORCID:0000000156559258)

doi:10.1038/s41467-025-65198-w

DOE OSTI · 2868458

The phase diagram of quantum chromodynamics in one dimension on a quantum computer

Than, Anton T. [University of Maryland, College Park, MD (United States)]·Atas, Yasar Y. [University of Waterloo, ON (Canada)] (ORCID:0000000275855973)·Chakraborty, Abhijit [University of Waterloo, ON (Canada)] (ORCID:0000000174879925)·Zhang, Jinglei [University of Waterloo, ON (Canada)] (ORCID:0000000231007921)·Diaz, Matthew T. [University of Maryland, College Park, MD (United States)]·Wen, Kalea [University of Maryland, College Park, MD (United States); College of William and Mary, Williamsburg, VA (United States)] (ORCID:0009000075349504)·Liu, Xingxin [University of Maryland, College Park, MD (United States)] (ORCID:0009000573278470)·Lewis, Randy [York University, Toronto, ON (Canada)] (ORCID:0009000548697155)·Green, Alaina M. [University of Maryland, College Park, MD (United States)] (ORCID:0000000333654433)·Muschik, Christine A. [University of Waterloo, ON (Canada); Perimeter Institute for Theoretical Physics, Waterloo, ON (Canada)] (ORCID:0000000245995107)·Linke, Norbert M. [University of Maryland, College Park, MD (United States); Duke University, Durham, NC (United States)] (ORCID:0000000156559258)

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Abstract

The quantum chromodynamics (QCD) phase diagram, which reveals the state of strongly interacting matter at different temperatures and densities, is key to answering open questions in physics, ranging from the behaviour of particles in neutron stars to the conditions of the early universe. However, classical simulations of QCD face significant computational barriers, such as the sign problem at finite matter densities. Quantum computing offers a promising solution to overcome these challenges. Here, we take an important step toward exploring the QCD phase diagram with quantum devices by preparing thermal states in one-dimensional non-Abelian gauge theories. We experimentally simulate the thermal states of SU(2) and SU(3) gauge theories at finite densities on a trapped-ion quantum computer using a variational method. This is achieved by introducing two features: Firstly, we add motional ancillae to the existing qubit register to efficiently prepare thermal probability distributions. Secondly, we introduce charge-singlet measurements to enforce colour-neutrality constraints. This work pioneers the quantum simulation of QCD at finite density and temperature for two and three colours, laying the foundation to explore QCD phenomena on quantum platforms.

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Than, Anton T. [University of Maryland, College Park, MD (United States)], Atas, Yasar Y. [University of Waterloo, ON (Canada)] (ORCID:0000000275855973), Chakraborty, Abhijit [University of Waterloo, ON (Canada)] (ORCID:0000000174879925), Zhang, Jinglei [University of Waterloo, ON (Canada)] (ORCID:0000000231007921), Diaz, Matthew T. [University of Maryland, College Park, MD (United States)], Wen, Kalea [University of Maryland, College Park, MD (United States); College of William and Mary, Williamsburg, VA (United States)] (ORCID:0009000075349504), Liu, Xingxin [University of Maryland, College Park, MD (United States)] (ORCID:0009000573278470), Lewis, Randy [York University, Toronto, ON (Canada)] (ORCID:0009000548697155), Green, Alaina M. [University of Maryland, College Park, MD (United States)] (ORCID:0000000333654433), Muschik, Christine A. [University of Waterloo, ON (Canada); Perimeter Institute for Theoretical Physics, Waterloo, ON (Canada)] (ORCID:0000000245995107), Linke, Norbert M. [University of Maryland, College Park, MD (United States); Duke University, Durham, NC (United States)] (ORCID:0000000156559258). 2025-11-21. The phase diagram of quantum chromodynamics in one dimension on a quantum computer. https://doi.org/10.1038/s41467-025-65198-w

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