Quantum entanglement is a phenomenon where the quantum states of particles are intrinsically linked, such that the state of one cannot be described independently of the others, even when separated by vast distances. As of 2025, the field has transitioned from foundational physics to large-scale systems engineering, focusing on two distinct scaling dimensions: quantity (multi-partite entanglement) and range (distance scaling).

Scaling Qubit Count (Multi-Partite) Expanding the number of simultaneously entangled qubits is essential for powerful quantum computing.

• Physical Qubits: Researchers using the Zuchongzhi superconducting quantum computer set a record by verifying the entanglement of 51 qubits, creating a complex system with no classical counterpart. Additionally, Caltech researchers successfully trapped 6,100 neutral atoms in an ...