4WP3.1 Quantum Channels OEAW,UNIGE,LMU,UG Milestones:M3.1.1 See two-photon interference signal after transmission of photons through >500m fibre (month 12)M3.1.2 Successful transmission of entanglement over >5km free-space link (month 9)Deliverables:D3.1.1 Comparison of fiber and free-space transmission of qubits (month 12)UNIGE part of 3.3
5Entanglement over 144km free-space In collaboration with:Free-Space distribution of entanglement and single photons over 144 km,R. Ursin, F. Tiefenbacher, T. Schmitt-Manderbach, H. Weier, T. Scheidl, M. Lindenthal, B. Blauensteiner, T. Jennewein, J. Perdigues, P. Trojek, B. Ömer, M. Fürst, M. Meyenburg, J. Rarity, Z. Sodnik, C. Barbieri, H. Weinfurter, A. Zeilinger, submitted
6La Palma - Tenerife Results Link performance:Bell S-Value:S=2,508+-0,037 in 221 sec.QKD Results:QBER 4,8%178 secret bits in 75 sec.
7WP3.2 Advanced sources of entangled photon pairs CNRSGRE OEAW UNIGE UBRISTOL Elsag KTH IDQUAN ULB Milestones:M3.2.1 Demonstration of narrow band bright time-bin entangled photon source (month 6)M3.2.2 Demonstration of polarization entanglement from ps-pulsed lasers (month 12)Deliverables:D3.2.1 Narrowband, bright entangled photon pair sources (12 month)
8Time-bin entangled sources UNIGE: Demonstration of a narrow-band bright time-bin entangled source based on PDC in periodically poled Lithium niobate waveguides and fibre bragg grating filters for the PDC photons at 10pm.CNRSGRETwo-photon excitation of an excitonic transition in a single CdSe/ZnSe quantum dot. Current problems: the excitation is not resonant.
9Advanced sources ~ 30% coincidence/single count ratio parameters: ~ 25 mW violet laser diode~ detected 805 nm~ 94% visibility of quantum correlations~ 30% coincidence/single count ratioused in advanced undegraduate labcourses at LMUcourse schedule:theory of parametric down-conversionbasics of state analysispreparation of distinct Bell statesmeasurement of correlation function in complementary bases (visibility)violation of Bell inequalitymeasurement of density matrix (fidelity of quantum state, entanglement witness, Peres-Horodecki criterium)
11HOM experiment using bright fibre sources 80 four-fold coincidences per sec.
12Bright entangled pair source in microstructured fibre 6000 pairs per secFidelity 89% with pure entangled stateTomography
13Further developments UB KTH Periodically poled twin hole fiber as source of photon pairs. Based onfiber optic source producing pairs at telecom wavelengths based on parametric down conversion.collaboration with Southampton UniversityPreliminary results: coincidencesKTHAsynchronous sources of heralded single photons at 1550nm
14WP3.3 Long distance fiber-optic quantum relays and purification OEAW,UNIGE,UBRISTOL,KTH,UG Milestones:M3.3.1 Remote Bell-state analysis achieved (month 9)M3.3.2 Two remote sources of entanglement operating synchronously (month 12)Deliverables:D3.3.1 Locking of remote lasers (month 12)
15Real World Q Teleportation BSM1: EPRqubitQM2: Distribute3: Create QubitEPR4: Prepare BSM5: BSM6: Send result7: Store photon8: Wait for BSMAnalysis9: AnalysisQMDistance: 550 mFibre: 800mO. Landry et al., quant-ph/
16Heralded Photon Q Teleportation &PC200 m200 mLaser fsLBOnn+1LBOnn+1Vraw=0.87+/-0.07Fraw=0.93+/-0.04Only those events that are coincident with the 4th photonare consideredO. Landry et al., quant-ph/
173- Bell-State Measurement teleportation Detect 3 of 4 Bell statesOnly requires two detectors andNo auxiliary photonsCompatible with polarisation encodingTeleportationF = 76%J. A. W. van Houwelingen et al., Phys. Rev. A, 74, (2006)
18Locking independent & remote lasers ?Quantum Memoryfirst successes (Lukin, Kimble)Entanglement Purificationfidelity F > 0.9 from 2 pairs of F = 0.75purification above local realism thresholdPan et al., al, Nature 423, 417 (2003)Walther et al., PRL 94, (2005)Entanglement swappingteleportation of entanglementfidelity F > 0.9 (sufficient to violate Bell‘s inequality)Jennewein et al. PRL 88, (2002), quant/phde Riedmatten et al., quant/ph
19Electronic synchronization of lasers UGfs Laser IElectronic synchronization80 MHz loop gain720 MHz loop gainfs Laser IIelectronic signal2,5 m1 km
20HOM with independent lasters UGindependent, spatially separated single-photon sourceselectronically synchronized fs mode locked lasers with a timing jitter of 260 fsprototype technology for quantum networking and quantum computingRealizing HOM visibility of entangled photons above 95% (APL, UIUC, UQ, UV)Develop improved (current 91% visibility) pulsed (Ti:Saph) source of entangled photons, maintaining HOM visibility > 90% while reducing spectral filtering requirements, enabling multi-source interference experiments and improving the rate of generation. (APL, UIUC, UQ, UV)V~83% VisibilityR. Kaltenbaek, B. Blauensteiner, M. Zukowski, M. Aspelmeyer, A. Zeilinger, PRL 96, (2006)
21WP3.3 Terrestrial and satellite free-space quantum communication OEAW,LMU,UBRISTOL Milestones:M3.4.1 Single link Bell-state analysis (month 6) (correlations are measured at Tenerifa – move to next period?)M3.4.2 Measurement of single photons reflected off a ranging satellite (month 12)Deliverables:D3.4.1 Specification of requirements of entanglement sources on satellites (month 9)
22Single photons from a Satellite Laser-RangingStation5860 kmSingle photons from a Satellite700-ps pulse17 kHz repetition rate0.1 photonP. Villoresi et al.: Space-to-ground quantum-communication, quant-ph/ ; P. Villoresi et al.: Experimental demonstration of a quantum communication channel from a LEO satellite to Earth, to be published
23WP3.5 Creation of entangled states of single atoms and photons by interference USTUTT Milestones:M3.5.1 Evaluation of production yield for different ion implantation strategy (month 6) APPLIED PHYSICS LETTERS 88 (2), (2006)M3.5.2 Evaluate the defect positioning accuracy (month 8) APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, 83 (2) (2006)Deliverables:D3.4.1 Writing NV defect patterns in type IIa diamond (month 9) JOURNAL OF PHYSICS-COND MAT 18 (21), 807-S824 (2006), PRL 97 (8) (2006)
24Entangling paramagnetic solid state systems Fault-tolerant repeater scheme with 2 Qbits per node:MD Lukin et al. PRL 96 (7): (2006)BvoltageLaser Detuning, GHz3Center BCenter A2211ABCreate,e.g. |0>A |1>B+ |1>A |0>B by ramantransitions.Solids:inhomogeneous broadening detunes A and Bexternal compensation field.P. Tamarat, PRL 97 (8): Art (2006)
25Electron nuclear spin entanglement Coop. with MD Lukin (Harvard)***Entanglement between electronand nuclear spins.L. Childress et al. Science DOI: /scienceRobustness of nuclear coherence during measurement on electron spinAfter measurement on electronspinRamsey fringes of singlenuclear spin coupled toelectron spin:Free evolutiontime /s
26Future ? WP 3.1 Quantum Channels Demonstration of a mobile polarization entangled photon source (Vienna)WP3.2 Advanced sources of entangled photon pairsPolarisation entangled photon source operating at telecom wavelengths (Vienna)Demonstration of a colinear, wavelength non-degenerate polarization entangled photon source (Vienna)WP 3.3 Long distance fiber-optic quantum relays and purificationM: Demonstration of the robustness of polarisation entanglement over long distance fiber transmission (>50 km) (Vienna)M: Locking of independent lasers separated by > 100 m (Vienna, 24 month)M: Synchronisation of ps lasers. (Geneva, 18 month)D: HOM dip between independent ps pumped entanglement sources. (Geneva, 24 month)WP 3.4 Terrestrial and satellite free-space quantum communicationM Single link Bell-state analyses (old one!) (Vienna)Analyze the influence of tracking on quantum communication in a satellite-ground link (Vienna)WP 3.5 Creation of entangled states of single atoms and photons by interferenceM1 Evaluate optimum method to generate electron-nuclear spin coherence. (Stutt, Period1+6)M2 Evaluate robustness of nuclear spin coherence during measurement on electron spin. (Stutt, Period1+9)D Swap of electron spin coherence and entanglement to nuclear spins. (Stutt, Period1+12)
27WP 3.5 Deliverables + Milestones Evaluation of production yield for different ion implantation strategy (due: month 6)APPLIED PHYSICS LETTERS 88 (2): Art. No (2006)M3.5.2Evaluate the defect positioning accuracy (due: month 8)APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, 83 (2): (2006)D3.5.1Writing NV defect patterns in type IIa diamond (due: month 9)JOURNAL OF PHYSICS-COND MAT 18 (21): S807-S824 (2006)PRL 97 (8): Art (2006)
28ULB contribution to WP3.2We have demonstrated a source of photon pairs based on parametric fluorescence in periodically poled twin hole fibers NBH1-06. As far as we know this is the only kind of fiber optics source of photon pairs that uses a chi_2 non linearity. If the source can be made more narrow band, it would be particularly useful for fiber optics quantum communication systems. Work on improving the source is under way. (This is a collaboration with Southampton University, where the samples are manufactured).No need to report the following:We have studied the possibility of using vector modulational instability in photonic crystal fibers as bright tunable fiber optics source of photon pairs. During preliminary work, we noticed some unexpected non linear effects that were reported in NHB2-06. Their relevance for such sources is under study.
29Entangled photons for relays M Demonstration of polarization entanglement from ps-pulsed lasers Achieved: Fulconis et al, Nature Photonics submittedD Narrowband, bright entangled photon pair sources In preparation: due m12
301400km distance ISS (International Space Station) WP 3.1 Space Quest ~400km from groundWP 3.1 Space QuestColumbus Module (ESA)1400km distanceOGS (ESA)Tenerife - SpainCalar Alto - Spain
31Time-bin entanglement sources Two-photon excitation of an excitonic transition in a single CdSe/ZnSe quantum dot. The green line is the frequency doubled laser frequency. In the middle trace the excitation is on resonance. In the top (bottom) trace the excitation is above (below) resonance and the second harmonic generation by the bulk crystal can be seen. This set of traces shows that this excitation is not resonant.
32WP 3.1 Space-QUEST Entanglement in Space Schedule: EM/EQM: 2010 Lunch: 2011Experiment:EM…. Engeneering moduleEQM… Engeneering qulified module (=flighmodule)