T C Ralph et al 2005 J. Opt. B: Quantum Semiclass. Opt. 7 S245 doi:10.1088/1464-4266/7/10/007
Adaptive phase measurements in linear optical quantum computation
T C Ralph1, A P Lund1 and H M Wiseman2
Show affiliationsPhoton counting induces an effective non-linear optical phase shift in certain states derived by linear optics from single photons. Although this non-linearity is non-deterministic, it is sufficient in principle to allow scalable linear optics quantum computation (LOQC). The most obvious way to encode a qubit optically is as a superposition of the vacuum and a single photon in one mode—so-called 'single-rail' logic. Until now this approach was thought to be prohibitively expensive (in resources) compared to 'dual-rail' logic where a qubit is stored by a photon across two modes. Here we attack this problem with real-time feedback control, which can realize a quantum-limited phase measurement on a single mode, as has been recently demonstrated experimentally. We show that with this added measurement resource, the resource requirements for single-rail LOQC are not substantially different from those of dual-rail LOQC. In particular, with adaptive phase measurements an arbitrary qubit state 
can be prepared deterministically.
- PACS
-
42.50.Ar Photon statistics and coherence theory
03.65.Ta Foundations of quantum mechanics; measurement theory
03.67.Lx Quantum computation architectures and implementations
- Subjects
- Dates
-
Issue 10 (October 2005)
Received 21 March 2005, accepted for publication 19 April 2005
Published 14 September 2005
-
Adaptive phase measurements in linear optical quantum computation
T C Ralph et al 2005 J. Opt. B: Quantum Semiclass. Opt. 7 S245
-
Specific Heat of Rhombohedral Polymeric C60 in Temperature Range 300–2 K
Cui Guang-Lei et al 2008 Chinese Phys. Lett. 25 658
-
A new algebraization of the Laméequation
Federico Finkel et al 2000 J. Phys. A: Math. Gen. 33 1519
-
Coherent Dynamics of Direct-Current-Driven Quantum-Dot-Array with Two Time-Dependent Embedded Impurities
Li Xiu-Ping et al 2008 Chinese Phys. Lett. 25 1396
-
XAFS study of the thermal behaviour of gold bulk and clusters
T Comaschi et al 2009 J. Phys.: Conf. Ser. 190 012122
-
Defects in amorphous Si1 − xGex alloys: An explanation of electron spin resonance signals
E. Kim et al 1997 Europhys. Lett. 40 147
-
On a possible mechanism for peripheral nerve stimulation during magnetic resonance imaging scans
Lawrence K Forbes and Stuart Crozier 2001 Phys. Med. Biol. 46 591
-
Formation of nanoporous titanium oxide films on silicon substrates using an anodization process
Xiaofeng Yu et al 2006 Nanotechnology 17 808
-
Eddy-damped quasinormal Markovian closure: a closure for magnetohydrodynamic turbulence?
Leaf Turner and Jane Pratt 2002 J. Phys. A: Math. Gen. 35 781
-
Coefficient of contribution to the combined standard uncertainty
Rüdiger Kessel et al 2006 Metrologia 43 S189
Related review articles
What's this?- Spin-to-orbital conversion of the angular momentum of light and its classical and quantum applications
- Solitons in nonlinear optics
- Single-photon generation and detection