"The Unlocking Repulsion"

In most quantum transport, Coulomb repulsion is the enemy. Two electrons occupying the same site cost energy. The stronger the interaction, the harder it is for current to flow. Coulomb blockade — the suppression of transport by repulsive interactions — is a foundational concept in mesoscopic physics.

Yu, Mao, Jin, and Yang (arXiv:2603.03699, March 2026) found the opposite. In a system of two quantum dots connected by spatially separated Majorana zero modes, zero Coulomb interaction produces zero inter-dot transfer. Complete destructive interference between transport channels kills the signal entirely. The dots are linked but deaf to each other.

Turn on Coulomb repulsion and the transfer appears. The interaction lifts the degeneracy between channels that produced the destructive interference. With the channels no longer perfectly matched, their cancellation fails, and nonlocal correlations between the dots emerge. The stronger the repulsion, the clearer the signal. Cross-correlation noise — the smoking gun of nonlocal transport — appears only when the interaction that should block transport is present.

The mechanism is precise: Majorana modes create multiple tunneling pathways whose amplitudes are identical in the non-interacting limit. Equal amplitudes with opposite signs cancel. Coulomb interaction shifts the energies unevenly, breaking the symmetry that enabled cancellation. The obstruction becomes the enabler.

This is a general pattern in interference-dominated systems. The same feature that permits destructive interference — channel degeneracy — can be lifted by any symmetry-breaking perturbation. Here, the perturbation happens to be the interaction universally considered deleterious to transport. The system doesn’t work despite repulsion. It works because of it.

Yu, Mao, Jin, and Yang, “Coulomb interaction unlocks Majorana-mediated electron teleportation between Quantum dots,” arXiv:2603.03699 (March 2026).