This study explores quantum critical phenomena in open quantum systems using a Rydberg quantum simulator. The researchers adiabatically prepare critical ground states of both a one-dimensional ring and a two-dimensional square lattice of cesium atoms. By tuning the openness of the system, they observe power-law correlations and extract scaling dimensions. In two dimensions, they identify two distinct boundary universality classes, demonstrating that direct adiabatic preparation of critical states can complement approaches using the Kibble-Zurek mechanism or digital quantum circuits. The study focuses on the Ising universality class, where quantum criticality is characterized by power-law decay of correlations. In one dimension, the researchers observe a power-law decay of the order parameter with an exponent of 2Δσ^1D = 1/4. In two dimensions, they find a power-law decay with an exponent of 2Δσ^2D = 0.59(9), consistent with conformal field theory predictions. The study also reveals that decoherence introduces a length scale that affects the observed correlations, and that boundary effects can lead to distinct phase transitions. The researchers use a programmable Rydberg simulator to prepare and characterize critical states, demonstrating the ability to observe quantum critical phenomena in open systems. They show that the critical behavior can be studied by tuning the system's openness and by observing the decay of correlations. The study highlights the importance of understanding quantum criticality in open systems and provides a framework for future experiments in this area. The results have implications for the study of quantum phase transitions and the development of quantum simulators.This study explores quantum critical phenomena in open quantum systems using a Rydberg quantum simulator. The researchers adiabatically prepare critical ground states of both a one-dimensional ring and a two-dimensional square lattice of cesium atoms. By tuning the openness of the system, they observe power-law correlations and extract scaling dimensions. In two dimensions, they identify two distinct boundary universality classes, demonstrating that direct adiabatic preparation of critical states can complement approaches using the Kibble-Zurek mechanism or digital quantum circuits. The study focuses on the Ising universality class, where quantum criticality is characterized by power-law decay of correlations. In one dimension, the researchers observe a power-law decay of the order parameter with an exponent of 2Δσ^1D = 1/4. In two dimensions, they find a power-law decay with an exponent of 2Δσ^2D = 0.59(9), consistent with conformal field theory predictions. The study also reveals that decoherence introduces a length scale that affects the observed correlations, and that boundary effects can lead to distinct phase transitions. The researchers use a programmable Rydberg simulator to prepare and characterize critical states, demonstrating the ability to observe quantum critical phenomena in open systems. They show that the critical behavior can be studied by tuning the system's openness and by observing the decay of correlations. The study highlights the importance of understanding quantum criticality in open systems and provides a framework for future experiments in this area. The results have implications for the study of quantum phase transitions and the development of quantum simulators.