Projects per year
Abstract
Photonic quantum systems are among the most promising architectures for quantum computers. It is well known that for dualrail photons effective nonlinearities and neardeterministic nontrivial twoqubit gates can be achieved via the measurement process and by introducing ancillary photons. While in principle this opens a legitimate path to scalable linear optical quantum computing, the technical requirements are still very challenging and thus other optical encodings are being actively investigated. One of the alternatives is to use singlerail encoded photons, where entangled states can be deterministically generated. Here we prove that even for such systems universal optical quantum computing using only passive optical elements such as beam splitters and phase shifters is not possible. This nogo theorem proves that photon bunching cannot be passively suppressed even when extra ancilla modes and arbitrary number of photons are used. Our result provides useful guidance for the design of optical quantum computers.
Original language  English 

Article number  1394 
Number of pages  6 
Journal  Scientific Reports 
Volume  3 
DOIs  
Publication status  Published  6 Mar 2013 
Austrian Fields of Science 2012
 103026 Quantum optics
 103008 Experimental physics
 210006 Nanotechnology
 103025 Quantum mechanics
Projects
 4 Finished

PhoCluDi: Photonic Cluster States From Diamond
Walther, P., Paulovics, V., Trupke, M. & Rudolph, T.
1/10/12 → 30/06/16
Project: Research funding

QuILMI: Quantum Integrated Light Matter Interface
Walther, P. & Paulovics, V.
1/10/12 → 31/03/16
Project: Research funding

Photonische Quantensimulationen
Walther, P. & Paulovics, V.
1/10/11 → 30/09/17
Project: Research funding