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Theses Defenses
October 14, 2022

Hour: 14:00h

Place: Auditorium

PhD THESIS DEFENSE: Investigating Quantum Many-Body Systems with Tensor Networks, Machine Learning and Quantum Computers

KORBINIAN KOTTMANN
Quantum Information Theory - Quantum Optics Theory, ICFO

We perform quantum simulation on classical and quantum computers and set up a machine learning framework in which we can map out phase diagrams of known and unknown quantum manybody systems in an unsupervised fashion. The classical simulations are done with state-of-the-art tensor network methods in one and two spatial dimensions. For one dimensional systems, we utilize matrix product states (MPS) that have many practical advantages and can be optimized using the efficient density matrix  enormalization group (DMRG) algorithm. The data for two dimensional systems is obtained from entangled projected pair states (PEPS) optimized via imaginary time evolution. Data in form of observables, entanglement spectra, or parts of the State vectors from these simulations, is then fed into a deep learning (DL) pipeline where we perform anomaly detection to map out the phase diagram. We extend this notion to quantum computers and introduce quantum variational anomaly detection. Here, we ˝rst simulate the ground state and then process it in a quantum machine learning (QML) manner. Both simulation and QML routines are performed on the same device, which we demonstrate both in realistic simulation and on a physical quantum computer hosted by IBM.

 

Thesis Directors: Prof Dr. Antonio Acín and Prof. Dr. Maciej Lewenstein

Theses Defenses
October 14, 2022

Hour: 14:00h

Place: Auditorium

PhD THESIS DEFENSE: Investigating Quantum Many-Body Systems with Tensor Networks, Machine Learning and Quantum Computers

KORBINIAN KOTTMANN
Quantum Information Theory - Quantum Optics Theory, ICFO

We perform quantum simulation on classical and quantum computers and set up a machine learning framework in which we can map out phase diagrams of known and unknown quantum manybody systems in an unsupervised fashion. The classical simulations are done with state-of-the-art tensor network methods in one and two spatial dimensions. For one dimensional systems, we utilize matrix product states (MPS) that have many practical advantages and can be optimized using the efficient density matrix  enormalization group (DMRG) algorithm. The data for two dimensional systems is obtained from entangled projected pair states (PEPS) optimized via imaginary time evolution. Data in form of observables, entanglement spectra, or parts of the State vectors from these simulations, is then fed into a deep learning (DL) pipeline where we perform anomaly detection to map out the phase diagram. We extend this notion to quantum computers and introduce quantum variational anomaly detection. Here, we ˝rst simulate the ground state and then process it in a quantum machine learning (QML) manner. Both simulation and QML routines are performed on the same device, which we demonstrate both in realistic simulation and on a physical quantum computer hosted by IBM.

 

Thesis Directors: Prof Dr. Antonio Acín and Prof. Dr. Maciej Lewenstein

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