Resources for Flexible Quantum Information Processing

Over the past two decades, quantum technologies for computation, communication and sensing have progressed from theoretical proposals to experimental reality. Although these technologies are widely expected to outperform their classical counterparts in the future, present day stateoftheart setups operating in the quantum domain cannot compete with currently available classical devices such as smart phones or laptop computers. This is, in part, due to the difficulties in controlling and precisely manipulating the required quantum systems such as trapped atoms or quanta of light (socalled photons). Consequently, modern prototypes for quantum computers operate with only a handful of information carrying systems called “qubits”, the quantum equivalents of classical bits.
In this research project, we investigate how the scarce quantum resources such as the available qubits can be used most efficiently to perform desired tasks such as running computations on a quantum computer. In particular, a novel aspect of this theoretical research project will be the focus on developing flexible multipurpose devices for quantumenhanced sensing and computation [Friis et al., New J. Phys. 19, 063044 (2017)]. That is, if resources are very limited and costly, it is desirable to design gadgets that are able to perform several tasks of interest using the same basic resources. The project is in this sense inspired by the technological miniaturization and functional integration that has taken place for modern smart phones. In our quest to develop flexible integrated quantum devices, we will hence study how resources for quantum computation and quantum communication can be converted and used most efficiently to perform also other tasks such as the precise measurement and estimation of unknown parameters. Apart from the conversion of informationtheoretic resources into each other, we will also consider the exchange with physical resources such as the available energy [e.g., conversion of energy into correlations, see Vitagliano, Klöckl, Huber, Friis, arXiv:1803.06884 or energy cost of measurements, see Guryanova, Friis, Huber, arXiv:1805.11899]. To achieve this, our research of computational and communicational tasks will be embedded in the context of physical theories such as quantum thermodynamics (e.g., to study the exchange and extraction of energy from systems with some temperature) and quantum optics (the interaction of light and matter in the quantum domain). Using these techniques, we will investigate, for example, how energy may be traded for information gain in the estimation of an unknown quantity, and how such tasks may be influenced by practical and fundamental limitations.
The project connects various aspects of my research in quantum thermodynamics, quantum metrology, quantum computation and entanglement detection.
In this research project, we investigate how the scarce quantum resources such as the available qubits can be used most efficiently to perform desired tasks such as running computations on a quantum computer. In particular, a novel aspect of this theoretical research project will be the focus on developing flexible multipurpose devices for quantumenhanced sensing and computation [Friis et al., New J. Phys. 19, 063044 (2017)]. That is, if resources are very limited and costly, it is desirable to design gadgets that are able to perform several tasks of interest using the same basic resources. The project is in this sense inspired by the technological miniaturization and functional integration that has taken place for modern smart phones. In our quest to develop flexible integrated quantum devices, we will hence study how resources for quantum computation and quantum communication can be converted and used most efficiently to perform also other tasks such as the precise measurement and estimation of unknown parameters. Apart from the conversion of informationtheoretic resources into each other, we will also consider the exchange with physical resources such as the available energy [e.g., conversion of energy into correlations, see Vitagliano, Klöckl, Huber, Friis, arXiv:1803.06884 or energy cost of measurements, see Guryanova, Friis, Huber, arXiv:1805.11899]. To achieve this, our research of computational and communicational tasks will be embedded in the context of physical theories such as quantum thermodynamics (e.g., to study the exchange and extraction of energy from systems with some temperature) and quantum optics (the interaction of light and matter in the quantum domain). Using these techniques, we will investigate, for example, how energy may be traded for information gain in the estimation of an unknown quantity, and how such tasks may be influenced by practical and fundamental limitations.
The project connects various aspects of my research in quantum thermodynamics, quantum metrology, quantum computation and entanglement detection.
Team
 Nicolai Friis (Project Leader, Institute for Quantum Optics and Quantum Information, IQOQI Vienna)
 Faraj Bakhshinezhad (External PhD student, Sharif University of Technology, Tehran, Iran)
 Tiago Debarba (Visiting Postdoc at IQOQI Vienna, Associate Professor at Universidade Tecnológica Federal do Paraná, Brazil)
 Beniamin Jablonski (MSc student, University of Vienna)
 Simon Morelli (PhD student, Institute for Quantum Optics and Quantum Information, IQOQI Vienna)