Demonstration of Quantum Entanglement in an Analog Electronic Device

There are a surprising number of classical analogs to phenomena generally regarded as uniquely quantum in nature. We consider one such analog that uses complex basebanded signals in a classical electronic device to represent a multi-qubit quantum state. Formally, such a representation is capable of reproducing the mathematical structure of a tensor-product Hilbert space. In particular, entangled bipartite states can be represented in this manner. As a demonstration of this concept, we describe an experiment using an analog electronic device capable of emulating an arbitrary two-qubit system. We then show how, using a pair of independent ``Alice'' and ``Bob'' analog measurement devices, one can achieve correlations in violation of Bell's inequality, much as those found in optical tests of quantum nonlocality.