A new preprint reports that a quantum resource called “magic” can be hidden in correlations between systems without entangling them. In the authors’ framework, the local pieces remain in the stabilizer set, while the global construction can retain the nonstabilizer resource and make it available when classical information is supplied or parties cooperate.
The work combines mathematical constructions and proofs with tests on a superconducting quantum processor. Those tests examined activation by a classical key, two-way state recovery and a secret-sharing protocol.
A resource hidden in global correlations
Here, “magic” refers to nonstabilizerness, a property outside the stabilizer set used in the framework. Local magic-freedom is defined by requiring each party’s marginal—the state visible to that party alone—to lie in its corresponding stabilizer set.
The central construction encodes any nonstabilizer state into a separable ENM state, meaning an entirely nonlocal magic resource, and then exactly recovers the original state using stabilizer protocols. A separate symmetric two-qubit construction is two-way separable ENM and attains optimal one-round local stabilizer extraction within the class studied by the authors.
The channel construction extends the idea to operations. It gives a reversible, separable ENM embedding with magic-free marginal dynamics, using a generic construction involving 3n qubits in total.
One two-qubit example, called a golden state, is separable and ENM while reaching the maximum two-qubit robustness of magic reported by the paper. The framework therefore pairs that global value with local marginals in the stabilizer set.
Keys and cooperation changed what could be recovered
The activation-key construction gives a locked-versus-unlocked test. When the key is withheld, the theory says the resulting operation is a complete-dephasing stabilizer channel. When the key is revealed, a Pauli correction can be applied to recover the intended T gate.
For each selected adjacent qubit pair, the researchers averaged process-tomography data over all 32 equally weighted key assignments before reconstructing the channel’s Choi state and evaluating its log-robustness of magic. The locked-mode diagnostic was consistently close to zero across all nine adjacent pairs, while the activated outputs agreed with the theoretical prediction.
A separate test used two spatially separated five-qubit blocks for a magic-secret-sharing protocol. The reconstructed Choi-state log-robustness was 0.83 with cooperation, compared with 0.18 in the no-cooperation control.
The two-way T- and F-type ENM-state tests covered five physical-qubit pairs. Reconstructed joint-state fidelities were approximately 0.982 to 0.992. Conditional extraction fidelities ranged from about 0.974 to 0.993 for the T state and from 0.970 to 1.000 for the F state.
The golden-state experiment reported state fidelities of approximately 0.993 to 0.998. Its global log-robustness of magic ranged from about 0.790 to 0.802, close to the paper’s reported optimum of 0.805, while the marginal log-robustness was 0, the stabilizer value.
A theory result with practical questions still open
The analysis extends beyond two qubits. The reversible construction produces bipartite separable ENM families on 2n qubits, with n qubits assigned to each party, and gives an exponentially growing lower bound on their robustness of magic.
The claims should be read within the paper’s stabilizer-resource framework. The experimental tests used selected qubit pairs, reconstructed states and channels, and specific protocols; they do not by themselves establish a general performance advantage for quantum hardware or show that entanglement is unnecessary for every quantum-information task.
The document is an arXiv preprint, version 1, dated 26 August 2026.
The authors interpret the findings as showing that entanglement is not required to distribute access to quantum computational power: magic can instead be encoded in separable correlations and activated, localized or secret-shared through classical information and cooperation.
Paper data and sources
Original title: Entirely nonlocal quantum magic without entanglement
Authors: Fuchuan Wei, Ruixia Wang, Yujia Zhang et al.
Journal/Repository: arXiv
Status: Preprint, not yet peer-reviewed
First online: 2026-08-26
DOI: Not available
Original paper · Full text