Related Experiment Video
Updated: Jun 24, 2025

Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators
Published on: May 30, 2014
Pseudomagic Quantum States
Andi Gu1, Lorenzo Leone2,3, Soumik Ghosh4
1Department of Physics, Harvard University, 17 Oxford Street, Cambridge, Massachusetts 02138, USA.
We introduce pseudomagic quantum states that appear computationally simple but are complex. These states reveal that quantum magic is a hidden property, not always apparent to observers with limited computational power.
Area of Science:
- Quantum Information Science
- Quantum Computing Theory
Background:
- Nonstabilizerness quantifies the nonclassical nature of quantum states, crucial for quantum advantage.
- Low nonstabilizerness in quantum states limits potential quantum computational advantage.
Purpose of the Study:
- Introduce "pseudomagic" ensembles of quantum states.
- Investigate the relationship between pseudomagic and pseudoentanglement.
- Explore applications in quantum scrambling, state synthesis, property testing, and cryptography.
Main Methods:
- Define and analyze pseudomagic ensembles.
- Compare pseudomagic with pseudoentanglement.
- Examine computational indistinguishability from the perspective of bounded observers.
Main Results:
- Pseudomagic states are computationally indistinguishable from high nonstabilizerness states despite having low nonstabilizerness.
- Pseudomagic does not follow from nor imply pseudoentanglement.
- Identified states from nonscrambling unitaries that are indistinguishable from scrambled states.
Conclusions:
- Nonstabilizerness is a "hide-able" characteristic of quantum states.
- Findings offer new insights into quantum scrambling and computational complexity.
- Demonstrate the physical significance of quantities measurable by computationally bounded observers.
Related Concept Videos
Quantum Numbers
The Quantum-Mechanical Model of an Atom
The de Broglie Wavelength
Atomic Nuclei: Nuclear Spin State Overview
The Pauli Exclusion Principle
Free Energy Changes for Nonstandard States
where R is the gas constant (8.314 J/K·mol), T is the absolute temperature in kelvin, and Q is the reaction quotient. This equation may be used to predict the spontaneity of a process under any given set of conditions.
Reaction Quotient...

