Contributed Talk 4: Paper 27: Limitations of gradient-based Born Machine over tensornetworks on learning quantum nonlocality

Nonlocality is an important constituent of quantum physics which lies at the heart of many striking features of quantum states such as entanglement. An important category of highly entangled quantum states are Greenberger-Horne-Zeilinger (GHZ) states which play key roles in various quantum-based technologies and are particularly of interest in benchmarking noisy quantum hardwares. A novel quantum inspired generative model known as Born Machine which leverages on probabilistic nature of quantum physics has shown a great success in learning classical and quantum data over tensor network (TN) architecture. To this end, we investigate the task of training the Born Machine for learning the GHZ state over two different architectures of tensor networks. Our result indicates that gradient-based training schemes over TN Born Machine fails to learn the non-local information of the coherent superposition (or parity) of the GHZ state. This leads to an important question of what kind of architecture design, initialization and optimization schemes would be more suitable to learn the non-local information hidden in the quantum state and whether we can adapt quantum-inspired training algorithms to learn such quantum states.