Skip to main content Accessibility help
×
  1. Home
  2. Browse subjects
  3. Engineering
  4. Communications, Signal Processing and Information Theory

Refine listing

Refine listing

Access:
Content type:
Publication date:
Apply   From and To filters
Subject: Show more
Journals Show more
Publishers: Show more
Societies Show more
Series: Show more
Collections: Show more

Actions for selected content:

Select all | Deselect all
  • View selected items
  • Export citations
  • Download PDF (zip)
  • Save to Kindle
  • Save to Dropbox
  • Save to Google Drive

Save Search

You can save your searches here and later view and run them again in "My saved searches".

Please provide a title, maximum of 40 characters.
Cancel
×

9096 results in Communications, Signal Processing and Information Theory

Page 49 of 455

  • 6 - Superconducting Qubits

  • Juan José García Ripoll
  • Book:
    Quantum Information and Quantum Optics with Superconducting Circuits
    Published online:
    04 August 2022
    Print publication:
    18 August 2022, pp 106-155

  • Summary

    We introduce the notion of qubit as unit of quantum information, illustrating how this notion can be implemented in nonlinear superconducting circuits via the charge and current degrees of freedom. Within these two types of qubits, we discuss the charge qubit, the transmon, and the flux qubit, illustrating the nature of the states that implement the qubit subspace and how they can be controlled and measured. We discuss how qubits can interact with each other directly or through mediators, illustrating different limits of interaction, introducing the notion of dipolar electric and magnetic moments, and demonstrating the tunability of interactions by different means. The chapter closes with a brief study of qubit coherence along the history of this field, with an outlook to potential near-term improvements.

  • 7 - Qubit–Photon Interaction

  • Juan José García Ripoll
  • Book:
    Quantum Information and Quantum Optics with Superconducting Circuits
    Published online:
    04 August 2022
    Print publication:
    18 August 2022, pp 156-197

  • Summary

    Almost all superconducting quantum technologies are built using a combination of qubits and microwave resonators. In this chapter, we develop the theory to study coherent qubit–photon interaction in such devices. We start with the equivalent of an atom in free space, studying a qubit in an open waveguide. We develop the spin-boson Hamiltonian, with specific methods to solve its dynamics in the limits of few excitations. Using these tools, we can study how an excited qubit can relax to the ground state, producing a photon, and how a propagating photon can interact with a qubit. We then move to closed environments where the photons are confined in cavities or resonators, developing the theory of cavity-QED. Using this theory, we study the Purcell enhancement of interactions, the Jaynes–Cummings model, Rabi oscillations, and vacuum Rabi splitting. We close the chapter illustrating some limits in which cavities can be used to control and measure qubits.

  • 5 - Microwave Photons

  • Juan José García Ripoll
  • Book:
    Quantum Information and Quantum Optics with Superconducting Circuits
    Published online:
    04 August 2022
    Print publication:
    18 August 2022, pp 63-105

  • Summary

    This chapter studies linear circuits built from capacitors, inductors, and waveguides. It shows how the excitations of these circuits are quantized and can be described as collections of quantum harmonic oscillators. It discusses the quantum states and quantum operations that are accessible by means of these circuits and external microwave drives. We show how to create coherent states, how microwave resonators decay and decohere, how to amplify and measure the quantum state of a resonator, and what states (e.g., Fock states, individual photons) require other, non-Gaussian means to be produced and detected.

Page 49 of 455