Nonstabilizerness (colloquially “magic”) characterizes genuinely quantum (beyond-Clifford) operations necessary for preparation of quantum states and can be measured by stabilizer Rényi entropy (SRE). For permutationally symmetric states, we show that the SRE depends, for sufficiently large systems, only on a constant number of expectation values of collective spin operators. This compact description is leveraged for analysis of spin-squeezing protocols, which inherently generate nonstabilizerness. Under one-axis twisting (OAT), the generation of optimal squeezing is accompanied by a logarithmic divergence of SRE with system size. Continued time evolution under OAT produces metrologically useful so-called kitten states, that is, superpositions of rotated Greenberger-Horne-Zeilinger states, that feature many-body Bell correlations but exhibit a smaller, system-size-independent SRE that decreases with increasing Bell-correlation strength. Our results reveal connections between nonstabilizerness, multipartite correlations, and quantum metrology and provide a practical route to quantify nonstabilizerness in experiments for precision sensing.

Close

PrevNext

View figure in article

• Quantum computation
• Quantum information theory
• Quantum metrology
• Quantum simulation