Engineering quantum electrodynamics

Y. N. Srivastava

Zuan Meng, Xin‐Ru Fang, Jingyu Zhang +4 more

Abstract A scheme is theoretically proposed to investigate a quantum Otto engine (QOE) based on cavity quantum electrodynamics (QED) systems, where the working substance consists of a single‐mode optical cavity coupled to either one or two identical two‐level atoms, corresponding to the Jaynes–Cummings (JC) and Tavis–Cummings (TC) models, respectively. These results show that quantum coherence can enhance the efficiency of the quantum Otto heat engine (QOHE) and that the QOE can operate in various thermodynamic modes, such as a heat engine, refrigerator, or heater. Building on these two cavity QED models, it is further demonstrated that increasing the number of atoms leads to an exponential enhancement in the work output of the QOHE. Finally, a localized quantum engine is analyzed by tracing out one of the atoms in the TC model and show that the local system can achieve an efficiency comparable to that of the global system. This work establishes a novel theoretical framework for understanding and optimizing the performance of quantum heat engines in cavity QED platforms.

Peter B. Renton

Joseph I. Kapusta, Charles Gale

Alireza R. Baghai-Wadji

Continuing size reduction in mesoscopic and nanoscopic electronic, photonic, and plasmonic devices makes the employment of quantum physics (QP) and quantum electrodynamics (QED) inevitable. Engineers at the forefront of these fields increasingly need to have a working knowledge of QP and, more importantly, feel confident to manoeuver through the intricate calculations involved. However, electrical engineers and applied physicists are typically unfamiliar with the sophisticated mathematical apparatus in QP and QED, which is generally perceived to be formidably abstract. The Mathematical Quantum Physics for Engineers and Technologists volumes aim to explain the mathematical foundation of QP and QED to engineers using an engineer's mindset as the starting point, and following a new line of thinking based on clarity and obviousness. Written for an audience of researchers and advanced students in electrical engineering, computer science, applied mathematics and applied physics, the Mathematical Quantum Physics for Engineers and Technologists volumes guide readers towards acquiring a solid understanding of the mathematical intricacies of quantum physics and quantum electrodynamics. Volume 2 covers topics including the ideal and perturbed quantum harmonic oscillator, the displacement operator, squeezed states, single electron systems, the Schrödinder picture, the Heisenberg picture, the Interaction picture, the Feynman path integral, the standard and generalized Trotter product formula, and quantum electrodynamics.

Eric C. Holland

Engineered quantum systems are poised to revolutionize information science in the near future. A persistent challenge in applied quantum technology is creating controllable, quantum interactions while preventing information loss to the environment, decoherence. In this thesis, we realize mesoscopic superconducting circuits whose macroscopic collective degrees of freedom, such as voltages and currents, behave quantum mechanically. We couple these mesoscopic devices to microwave cavities forming a cavity quantum electrodynamics (QED) architecture comprised entirely of circuit elements. This application of cavity QED is dubbed Circuit QED and is an interdisciplinary field seated at the intersection of electrical engineering, superconductivity, quantum optics, and quantum information science. Two popular methods for taming active quantum systems in the presence of decoherence are discrete feedback conditioned on an ancillary system or quantum reservoir engineering. Quantum reservoir engineering maintains a desired subset of a Hilbert space through a combination of drives and designed entropy evacuation. Circuit QED provides a favorable platform for investigating quantum reservoir engineering proposals. A major advancement of this thesis is the development of a quantum reservoir engineering protocol which maintains the quantum state of a microwave cavity in the presence of decoherence. This thesis synthesizes strongly coupled, coherent devices whose solutions to its driven, dissipative Hamiltonian are predicted a priori. This work lays the foundation for future advancements in cavity centered quantum reservoir engineering protocols realizing hardware efficient circuit QED designs.