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

Europhysics Letters (EPL)

Energy measurements and preparation of canonical phase states of a nano-mechanical resonator

Kurt A. Jacobs, Andrew N. Jordan, E. K. Twyeffort Irish

Published Mar 12, 2008• 19 citations
Publisher

Abstract

We show that a continuous quantum non-demolition measurement of the energy of a nanomechanical resonator can be achieved by monitoring the resonator with a single-electron transistor, or a quantum point contact, via a Cooper-pair box. This technique can further be used to prepare highly entangled states of two resonators, such as canonical phase reference states, and so-called noon states.

DOI
10.1209/0295-5075/82/18003

Related papers

Energy Measurements and Preparation of Canonical Phase States of a Nano-Mechanical Resonator

Kurt A. Jacobs, Andrew N. Jordan, E. K. Twyeffort Irish

We show that a continuous quantum non-demolition measurement of the energy of a nanomechanical resonator can be achieved by monitoring the resonator with a quantum point contact via a Cooper-pair box. This technique can further be used to prepare highly non-classical states of two resonators, such as canonical phase-reference states, and so-called "noon" states.

arXiv:0707.3803•Jul 25, 2007•0 citations

Continuous Measurement of the Energy Eigenstates of a Nanomechanical Resonator without a Nondemolition Probe

Kurt A. Jacobs, Pavel Lougovski, M. P. Blencowe

We show that it is possible to perform a continuous measurement that continually projects a nanoresonator into its energy eigenstates by employing a linear coupling with a two-state system. This technique makes it possible to perform a measurement that exposes the quantum nature of the resonator by coupling it to a Cooper-pair box and a superconducting transmission line resonator.

arXiv:quant-ph/0607102•Physical Review Letters•Apr 2, 2007•47 citations

Quantum measurement of a coupled nanomechanical resonator–Cooper-pair box system

E. K. Twyeffort Irish, Keith Schwab

We show two effects as a result of considering the second-order correction to the spectrum of a nanomechanical resonator electrostatically coupled to a Cooper-pair box. The spectrum of the Cooper-pair box is modified in a way which depends on the Fock state of the resonator. Similarly, the frequency of the resonator becomes dependent upon the state of the Cooper-pair box. We consider whether these frequency shifts could be utilized to prepare the nanomechanical resonator in a Fock state, to perform a quantum non-demolition measurement of the resonator Fock state, and to distinguish the phase states of the Cooper-pair box.

arXiv:cond-mat/0301252•Physical Review B•Oct 15, 2003•195 citations

Emergent quantum jumps in a nano-electro-mechanical system

Kurt Jacobs, Pavel Lougovski

We describe a nano-electro-mechanical system that exhibits the 'retroactive' quantum jumps discovered by Mabuchi and Wiseman (1998 Phys. Rev. Lett. 81 4620). This system consists of a Cooper-pair box coupled to a nano-mechanical resonator, in which the latter is continuously monitored by a single-electron transistor or quantum point contact. Further, we show that these kinds of jumps, and the jumps that emerge in a continuous quantum non-demolition measurement, are one and the same phenomena. We also consider manipulating the jumps by applying feedback control to the Cooper-pair box.

arXiv:quant-ph/0606060•Journal of Physics A Mathematical and Theoretical•Oct 31, 2007•0 citations

Quantum Nondemolition Squeezing of a Nanomechanical Resonator

Rusko Ruskov, Keith Schwab, Alexander N. Korotkov

We show that the nanoresonator position can be squeezed significantly below the ground state level by measuring the nanoresonator with a quantum point contact or a single-electron transistor and applying a periodic voltage across the detector. The mechanism of squeezing is basically a generalization of quantum nondemolition measurement of an oscillator to the case of continuous measurement by a weakly coupled detector. The quantum feedback is necessary to prevent the "heating" due to measurement back-action. We also discuss a procedure of experimental verification of the squeezed state.

arXiv:cond-mat/0406416•IEEE Transactions on Nanotechnology•Jan 1, 2005•10 citations

Continuous quantum nondemolition measurement of Fock states of a nanoresonator using feedback-controlled circuit QED

M. J. Woolley, Andrew C. Doherty, Gerard J Milburn

We propose a scheme for the quantum nondemolition (QND) measurement of Fock states of a nanomechanical resonator via feedback control of a coupled circuit QED system. A Cooper pair box (CPB) is coupled to both the nanoresonator and microwave cavity. The CPB is readout via homodyne detection on the cavity and feedback control is used to effect a nondissipative measurement of the CPB. This realizes an indirect QND measurement of the nanoresonator via a second-order coupling of the CPB to the nanoresonator number operator. The phonon number of the Fock state may be determined by integrating the stochastic master equation derived, or by processing of the measurement signal.

arXiv:1002.4055•Physical Review B•Sep 14, 2010•19 citations
We show that a continuous quantum non-demolition measurement of the energy of a nanomechanical resonator can be achieved by monitoring the resonator with a single-electron transistor, or a quantum point contact, via a Cooper-pair box. This technique can further be used to prepare highly entangled states of two resonators, such as canonical phase reference states, and so-called noon states.
We show two effects as a result of considering the second-order correction to the spectrum of a nanomechanical resonator electrostatically coupled to a Cooper-pair box. The spectrum of the Cooper-pair box is modified in a way which depends on the Fock state of the resonator. Similarly, the frequency of the resonator becomes dependent upon the state of the Cooper-pair box. We consider whether these frequency shifts could be utilized to prepare the nanomechanical resonator in a Fock state, to perform a quantum non-demolition measurement of the resonator Fock state, and to distinguish the phase states of the Cooper-pair box.
We describe a nano-electro-mechanical system that exhibits the 'retroactive' quantum jumps discovered by Mabuchi and Wiseman (1998 Phys. Rev. Lett. 81 4620). This system consists of a Cooper-pair box coupled to a nano-mechanical resonator, in which the latter is continuously monitored by a single-electron transistor or quantum point contact. Further, we show that these kinds of jumps, and the jumps that emerge in a continuous quantum non-demolition measurement, are one and the same phenomena. We also consider manipulating the jumps by applying feedback control to the Cooper-pair box.
We show that the nanoresonator position can be squeezed significantly below the ground state level by measuring the nanoresonator with a quantum point contact or a single-electron transistor and applying a periodic voltage across the detector. The mechanism of squeezing is basically a generalization of quantum nondemolition measurement of an oscillator to the case of continuous measurement by a weakly coupled detector. The quantum feedback is necessary to prevent the "heating" due to measurement back-action. We also discuss a procedure of experimental verification of the squeezed state.
We propose a scheme for the quantum nondemolition (QND) measurement of Fock states of a nanomechanical resonator via feedback control of a coupled circuit QED system. A Cooper pair box (CPB) is coupled to both the nanoresonator and microwave cavity. The CPB is readout via homodyne detection on the cavity and feedback control is used to effect a nondissipative measurement of the CPB. This realizes an indirect QND measurement of the nanoresonator via a second-order coupling of the CPB to the nanoresonator number operator. The phonon number of the Fock state may be determined by integrating the stochastic master equation derived, or by processing of the measurement signal.