Fundamental Spacetime Representations of Quantum Antenna Systems

Abstract

We develop foundations for the emerging field of quantum antennas using relativistic quantum field theory. We show that the concept of "antenna" goes beyond electromagnetic waves. Any quantum radiation can be treated within quantum antenna theory, not only electromagnetic or acoustic radiation that dominated the field so far.

Markovian Quantum Antenna Theory

“…For example, ideas from computational electromagnetics [1] were proposed for solving problems in the field of computational quantum information processing [2], [3]. Moreover, there has been some progress in areas like basic theory [4]- [8] and atom-radiation structures and quantum control for various applications [9]- [17]. At the same time, one finds in the earlier (and better known) fields of quantum computing and quantum information a natural connection with some of the well-established systems in electromagnetic theory and electromagnetic engineering, e.g., quantum waveguides [18], quantum microwave circuits [19], and quantum antennas [9].…”

“…Quantum antenna (QA) systems belong to future and current applications in the general area of digital and continuous quantum communications, in addition to other related research domains such as quantum computing, quantum imaging, quantum tomography, and nanotechnology. Initially developed from within already existing larger disciplines such as quantum technologies [22], [23], quantum electromagnetics [2], [3], [5]- [7], [24], and optical antennas [25], [26], quantum antenna theory [8]- [10], [27]- [29] is an emerging crossdisciplinary field cutting through both classical and quantum ideas and methods. The subject of quantum antennas enjoys a considerable range of existing and potential applications in various fields.…”

“…Indeed, quantum mechanics is not a specific theory, but a general framework that may be applied to a large (if not all) known physical and engineering phenomena [32]. 2 However, while throughout its short history quantum antennas have been often approached from within the field of quantum optics, e.g., see [10] and the numerous references cited therein, one of the principal objectives of general quantum antenna theory, when seen as a subdiscipline of quantum engineering, is to understand the fundamental principles of quantum antennas relative to classical antennas [33], [34], especially in light of the fact that the concept of quantum radiation is intrinsically broader and wider in scope than acoustic or electromagnetic radiation [8]. In other words, one of the main objectives of quantum 2 For instance, this fact was recently exploited by using quantum field theory (QFT) to show that the concept of a generic quantum antenna is general enough to include all types of radiation particles that may be used to encode and transmit classical or quantum information in myriad different ways [8].…”

“…antenna theory should be investigating how previous wellestablished ideas and methods, which have been successfully utilized in classical antenna theory, can be profitably exploited, extended, and applied to handle the quantum system [8], [28], [29]. In other words, quantum antenna theory should not be restricted to only trying to understand how purely non-classical behaviour emerges in the quantum case.…”

“…1. This is a highly nontrivial problem given that quantum antennas are fundamentally nonlinear systems when it comes to the relation between the input and output information states [8], [10], [29]. However, as will be demonstrated below, the coupling matrix γ κi (see Fig.…”