A recent study published in the journal Physical Review Letters introduces the concept of pseudo-materials quantum states that have a high degree of complexity and can bring the achievement of quantum superiority. Quantum superiority refers to the ability of quantum computers to perform calculations that are inaccessible to classical computers due to their limited computing capabilities. The study focuses on achieving universal quantum calculations, which is at the core of this concept.
The researchers at PRL are studying unreasoned states, or magical states, that allow for quantum calculations beyond the reach of effective simulation on classical computers. This challenge is what endows quantum computers with their potential power.
Physicist.org interviewed the co-authors of the study, Harvard University graduate student Andi GU and Free University of Berlin postdoctoral researcher Dr. Lorenzo Leone. GU emphasized that quantum calculations exhibit more power than classical ones, using terms like “non-attainive” or “magic” to describe the extent of non-classical resources that a quantum state possesses.
Stabilized and Unstable Quantum States
Every quantum system can be defined by a quantum state, a mathematical equation containing all information about the system. A stabilized state is a type of quantum state that can be effectively simulated on a classical computer. Dr. Leone explained that these states, along with a limited set of quantum operations, establish a classically simulated structure but fall short of achieving true universal quantum calculations. To conduct genuinely quantum operations surpassing classical computers, unstable states are necessary, which are complex to create due to the requirement of more sophisticated quantum operations.
GU highlighted the role of non-attainiveness as a resource for achieving quantum superiority: the more non-attainiveness in a quantum state, the more powerful it becomes as a resource for quantum calculations.
Pseudo-Magical States
The researchers introduced the concept of pseudo-magical quantum states possessing characteristics of unstable states while appearing as random quantum states to an observer with limited computing resources. This implies that pseudo-magical states seem magical but are much simpler to generate.
Dr. Leone mentioned that distinguishing pseudo-magical states from genuine magic requires an exponential amount of computational resources, rendering it infeasible for a real observer. GU added that pseudo-magical conditions are crafted to appear highly unstable for observers with limited quantum capabilities.