The quantum Mpemba effect is a paradoxical phenomenon in which a state with greater initial symmetry breaking restores symmetry faster. Theoretically predicted for integrable and chaotic systems, experimental studies, especially of flexible modulation, have remained limited. Nearby in the archive are works on the quantum Mpemba effect in open systems, its connection to chaos and entanglement, and observations in ion traps. This work fills a gap: it systematically explores the influence of interaction range, local potentials, and initial state choice on a single platform.
The experiment was performed on a 16-qubit superconducting processor with a ring topology and tunable couplings. 14 qubits form a chain, where nearest-neighbor couplings are set by capacitive elements and long-range couplings go through a central tunable resonator. The ratio of nearest-neighbor to long-range coupling r was varied from 10 to 1 by changing frequency detunings. Initial states were tilted Néel and ferromagnetic product states with tilt angles π/4 and π/2. To measure entanglement asymmetry (EA), quantum tomography of a three-qubit subsystem was performed: 27 measurement bases, density matrix reconstruction via least squares with physical constraints. The matrix was then projected onto charge sectors, and the difference of von Neumann entropies was computed.
In the strong nearest-neighbor coupling regime (r≈10), the EA curves for states with angles π/4 and π/2 cross: the state with greater symmetry breaking restores symmetry faster, a clear signature of the quantum Mpemba effect. In the intermediate regime (r≈1), the crossing disappears: EA decays monotonically, and the entanglement entropy reaches the Page value, indicating suppression of the effect upon thermalization. The effect was restored in two ways: by introducing a linear potential on the sites (W=6 MHz), which suppresses ergodicity more strongly for the smaller tilt angle, and by starting from tilted ferromagnetic states, where the dynamics reduces to the Lipkin–Meshkov–Glick model. In the second case, the EA crossing persists even under strong on-site disorder (uniform distribution in the range ±14g), unlike previous ion-trap experiments.
The work shows that the quantum Mpemba effect is not an exotic curiosity but a controllable property of nonequilibrium dynamics. Unlike neighboring studies, where the effect was observed in a single configuration, here multidimensional modulation is demonstrated: changing interaction range, local potentials, and initial states. This provides universal knobs for controlling relaxation and links symmetry restoration to thermalization and ergodicity.
Possible directions include studying the effect in the prethermalization regime, under other symmetries (Z₂, SU(2)), and with symmetry-breaking Hamiltonians. It is interesting to explore the connection to accelerated qubit reset and state preparation.
The results could accelerate the development of qubit reset and quantum state preparation protocols, and deepen understanding of nonequilibrium many-body physics.
Test the Mpemba effect in the prethermalization regime and for other symmetries, and investigate the dynamics of EA under symmetry-breaking Hamiltonians.
The work directly addresses the fundamental problem of the connection between symmetry and thermalization in isolated quantum systems, as well as the role of ergodicity in nonequilibrium dynamics.
This section is addressed to the author of the paper and their colleagues. Neighbouring works were found by meaning-based search across our archive, not by word overlap. We do not review: we show the field around the work.
What the work does
The study demonstrates the quantum Mpemba effect on a 16-qubit superconducting processor with tunable couplings. The authors measure entanglement asymmetry using quantum tomography and show that the effect arises in the regime of strong nearest-neighbor couplings, is suppressed in the intermediate regime, and is restored when a linear potential is introduced or when starting from tilted ferromagnetic states.
Where its strength is
A systematic investigation of the influence of interaction range, local potentials, and initial-state choice on a single experimental platform, providing multidimensional control over the quantum Mpemba effect.
Where it could go next
Worth trying
Why this may matter
Controlling the quantum Mpemba effect could open new ways to accelerate relaxation in quantum devices and improve control over the non-equilibrium dynamics of many-body systems.
Nearby works in our archive
The closest work in the archive sits at 0.64 by meaning — the usual level for our corpus.
The classical Mpemba effect was first described by schoolboy Erasto Mpemba in 1963, when he noticed that hot ice cream freezes faster than cold.