Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Springer proceedings in physics

Continuous-Mode Theory of Quantum-Optical Processing

John Jeffers, R. Loudon, K. J. Blow, Simon J. D. Phoenix

Published Jan 1, 1991• 2 citations
Publisher
DOI
10.1007/978-3-642-76373-1_2

Related papers

Discrete-Mode Theory of Quantum-Optical Processing

R. Loudon

Springer proceedings in physics•Jan 1, 1991•1 citation

Pumping an atom laser

G. R. Dennis

Measurement is our fundamental tool for learning about the world around us. It is from observing trends in measurements that we develop the theories that enable us to predict future behaviour, and it is against measurements that we determine the validity of these theories. Increases in the precision of our measurements are fundamental to our understanding. Atom interferometry is a new method for performing precision measurements that uses the matter-wave nature of atoms to perform interferometry experiments analogous to those performed with photons. However, in contrast to optical interferometry, which uses coherent sources of photons, atom interferometry uses thermal atomic sources, in part due to the unavailability of high-flux coherent atomic sources. Although pulsed coherent atomic sources are presently available, continuous sources are not. Creating a truly continuous coherent source for atoms is tricker than for photons. One of the largest challenges is that atom number is conserved. A source of atoms is therefore necessary to produce a truly continuous atom laser. This source must be used to replenish the lasing mode of the atom laser, and the process must operate without significantly disturbing the coherence properties of the lasing mode. It is this replenishment or pumping process that has been investigated theoretically in this thesis. There are only two choices for the reservoir that makes the replenishment (or pumping) process of an atom laser irreversible: the empty modes of the optical field, and the empty modes of the atomic field. Processes of both forms are considered. Using an optical reservoir has the advantage that atoms are not necessarily lost as part of the pumping process, which is necessary when using an atomic reservoir. The efficiency of processes using an optical reservoir can therefore be higher. Using an atomic reservoir, however, has the advantage that it is easier to implement as one can use the standard experimental technique of evaporation which is commonly used in the production of pulsed coherent atomic sources. We show theoretically in this thesis that although it is possible to produce a continuous atom laser using an atomic reservoir, the flux achieved in the geometry considered is insufficient to compete with pulsed coherent atomic sources for precision measurement. The results for the pumping process using an optical reservoir are more promising. Although condensed sources were used as the source for this process, a detailed comparison of the theoretical calculations and experimental results indicate that the detrimental reabsorption processes are suppressed. This suggests that it may be possible to use higher-flux thermal atomic sources to replenish the lasing mode of an atom laser with this pumping process.

•Jan 1, 2010•1 citation

Quantum Optical Processes: From Basics to Applications

Sintayehu Tesfa

•Feb 4, 2021•3 citations

Quantum computation with continuous variables

Pieter Kok, Brendon W. Lovett

In the previous chapter we have discussed some important quantum information processing techniques based on continuous variables, or ‘qunats’. In this chapter, we describe methods for extending these techniques to quantum computation with optical qunats. We will first show in Section 9.1 how the optical qunat states are initialized using single-mode squeezing, and we give optical implementations of some of the most important single-qunat gates, such as the Heisenberg-Weyl operators and the Fourier transform. In Section 9.2, we study the theory of two-mode Gaussian operations, and we construct a general optical circuit that can implement any two-mode Gaussian operation. In Section 9.3, we introduce the stabilizer formalism for qunats, and use it to derive a Gottesman-Knill theorem. This leads to the general requirement of nonlinear gates for qunats, and their optical implementation will be discussed in Section 9.4. Having thus established the optical implementation of universal quantum computing with continuous variables, we extend this to the one-way model in Section 9.5, where we introduce cluster states for continuous variables. Finally, in Section 9.6, we discuss various quantum error-correction techniques for qunat quantum computing. Single-mode optical qunat gates We have already seen in Chapter 2 that the single qunat gates are fundamentally different from qubit gates. In the context of optical implementations, this difference arises due to the complementary nature of qubits and qunats: qubits that are represented by single photons can be considered particles, whereas qunats are encoded in the wave properties of the optical field.

Cambridge University Press eBooks•Apr 22, 2010•2 citations

Theory for continuous quantum measurements of two-mode fields

Tatiana M. Maevskaya, S. Ya. Kilin

A simulation scheme for the photodetection process of two-mode fields with the continuous measurements of one and both modes is presented. Continuous reduction of the two-mode field during the measurement is described. Analytical expressions for statistic characteristics of the monitored radiation are obtained.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•May 6, 1996•0 citations

Quantum Optical Processes

Sintayehu Tesfa

Lecture notes in physics•Jan 1, 2020•0 citations
Measurement is our fundamental tool for learning about the world around us. It is from observing trends in measurements that we develop the theories that enable us to predict future behaviour, and it is against measurements that we determine the validity of these theories. Increases in the precision of our measurements are fundamental to our understanding. Atom interferometry is a new method for performing precision measurements that uses the matter-wave nature of atoms to perform interferometry experiments analogous to those performed with photons. However, in contrast to optical interferometry, which uses coherent sources of photons, atom interferometry uses thermal atomic sources, in part due to the unavailability of high-flux coherent atomic sources. Although pulsed coherent atomic sources are presently available, continuous sources are not. Creating a truly continuous coherent source for atoms is tricker than for photons. One of the largest challenges is that atom number is conserved. A source of atoms is therefore necessary to produce a truly continuous atom laser. This source must be used to replenish the lasing mode of the atom laser, and the process must operate without significantly disturbing the coherence properties of the lasing mode. It is this replenishment or pumping process that has been investigated theoretically in this thesis. There are only two choices for the reservoir that makes the replenishment (or pumping) process of an atom laser irreversible: the empty modes of the optical field, and the empty modes of the atomic field. Processes of both forms are considered. Using an optical reservoir has the advantage that atoms are not necessarily lost as part of the pumping process, which is necessary when using an atomic reservoir. The efficiency of processes using an optical reservoir can therefore be higher. Using an atomic reservoir, however, has the advantage that it is easier to implement as one can use the standard experimental technique of evaporation which is commonly used in the production of pulsed coherent atomic sources. We show theoretically in this thesis that although it is possible to produce a continuous atom laser using an atomic reservoir, the flux achieved in the geometry considered is insufficient to compete with pulsed coherent atomic sources for precision measurement. The results for the pumping process using an optical reservoir are more promising. Although condensed sources were used as the source for this process, a detailed comparison of the theoretical calculations and experimental results indicate that the detrimental reabsorption processes are suppressed. This suggests that it may be possible to use higher-flux thermal atomic sources to replenish the lasing mode of an atom laser with this pumping process.
In the previous chapter we have discussed some important quantum information processing techniques based on continuous variables, or ‘qunats’. In this chapter, we describe methods for extending these techniques to quantum computation with optical qunats. We will first show in Section 9.1 how the optical qunat states are initialized using single-mode squeezing, and we give optical implementations of some of the most important single-qunat gates, such as the Heisenberg-Weyl operators and the Fourier transform. In Section 9.2, we study the theory of two-mode Gaussian operations, and we construct a general optical circuit that can implement any two-mode Gaussian operation. In Section 9.3, we introduce the stabilizer formalism for qunats, and use it to derive a Gottesman-Knill theorem. This leads to the general requirement of nonlinear gates for qunats, and their optical implementation will be discussed in Section 9.4. Having thus established the optical implementation of universal quantum computing with continuous variables, we extend this to the one-way model in Section 9.5, where we introduce cluster states for continuous variables. Finally, in Section 9.6, we discuss various quantum error-correction techniques for qunat quantum computing. Single-mode optical qunat gates We have already seen in Chapter 2 that the single qunat gates are fundamentally different from qubit gates. In the context of optical implementations, this difference arises due to the complementary nature of qubits and qunats: qubits that are represented by single photons can be considered particles, whereas qunats are encoded in the wave properties of the optical field.