Photon Temporal Modes as a Quantum Information Resource

University Of Oregon Eugene, Eugene OR

Investigators

Abstract

This project aims to develop a new approach for using photons of light to encode quantum information. In a quantum information network, whose purpose is to store, transmit and manipulate information in ways not possible using classical physics techniques, photons transfer quantum information between network nodes. Single photons are characterized by their color (frequency), polarization orientation, spatial beam profile, and temporal shape. Only recently has the temporal shape of photons been recognized as an underutilized resource for encoding quantum information. The PI will develop methods to encode quantum information in the temporal shape of single-photon wave packets, and to demonstrate means for manipulating such encoded information. This research has the potential to advance quantum information science by improving the ability to store larger amounts of information in single photons in a manner that is compatible with optical-fiber networks. The research will impact the growing field of quantum information technology, including quantum computing, and offers excellent opportunities to integrate science education with research. The research builds on the PI's recent successful demonstration of the crucially needed information-processing device - the quantum pulse gate - that is capable of sorting (and routing) optical pulses according to their temporal shape. The research aims to develop the complete set of conceptual and practical tools needed for performing quantum information operations using temporal (wave-packet) modes of light. Temporal modes (TMs) form a discrete set of field-orthogonal pulse shapes that occupy the same region of time-frequency (phase) space. The researchers recently experimentally demonstrated their proposed method for separating (sorting) temporal modes by using a novel form of optical frequency conversion. Unlike polarization, which is fundamentally a two-state system, the temporal-mode basis offers the possibility for multi-level quantum logic (qudits). For TMs to rise to their potential as a tool for quantum information science, it needs to be demonstrated that all of the quantum resources and operations needed for QIS with temporal modes are available. Specifically, the researchers will work to demonstrate: 1) a source of TM-entangled photons, 2) quantum state tomography in the TM basis, 3) quantum process tomography of the QPG device itself, and 4) coherent and efficient manipulation of light in field-orthogonal TMs to implement single-photon quantum logic gates. Controlling the states of quantum systems is of broad interest in science and information technology, metrology, quantum chemistry, and nano-mechanics. Optical technology and quantum-optics-based information science offer excellent opportunities to integrate research with science education. The PI cofounded in 2010 the Science Literacy Program (SLP) at the University of Oregon, and served as Co-Director, and is currently on the Advisory Board. The SLP provides mentored instructional opportunities to many graduate students and undergraduate science majors serving as co-instructors in science literacy courses, which have impacted thousands of students at the university. During this project the PI will teach and mentor instructors for an SLP course that presents quantum information science to non-science majors, using inquiry-based-learning techniques to engage students. The PI has published a popular-level book for the course, Quantum Physics: What Everyone Needs to Know (Oxford, 2017), and will continue promoting education using material from this book as part of this project. A PhD student working in quantum information science research served as co-instructor to plan the course learning goals, prepare and present several class lectures, write homework and exam questions, and facilitate group problem-solving activities during class sessions. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.