Ph.D. Student: Alessio Avella
Tutor Unito: Prof. Mauro Anselmino
Tutor INRiM: Dott. Marco Genovese
Graduate School on Physics and Astrophysics XXVI cicle
Introduction
Quantum Cryptography
Quantum Metrology Quantum Information
Foundation of Quantum Meccanics
Quantum Imaging
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Absolute calibration technique for photon number resolving detectors
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Integrated optical device
Measurement
Quantum states generation
Photon sources
Photon detectors
Quantum states
generation
Quantum state manipulation
Quantum state
measurement
Quantum memory
Introduction
Self consistent, absolute calibration technique for photon number resolving detectors.
Measurement of high degree of entanglement and nonlocality of a two-photon state.
Engeeniring and measurement of spectral property of two-photon states.
Homodyne detection and application to experiment about foundation of quantum meccanics.
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Absolute calibration technique for photon number resolving detectors
Self consistent, absolute calibration technique for photon number resolving detectors.
A. Avella, G. Brida, I. P. Degiovanni, M. Genovese, M. Gramegna, L. Lolli, E. Monticone, C. Portesi, M. Rajteri, M. L. Rastello, E. Taralli, P. Traina, and M. White.
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Absolute calibration technique for photon number resolving detectors
Single Photon Avalance Diode (SPAD)
Transition Edge Sensor (TES)
Photomultiplier tube
The ideal detector should fulfill the following requirements:
• high quantum detection efficiency over a
large spectral range. • small probability of generating noise. • small jitter. • short dead time.
The ideal detector should fulfill the following requirements: • high quantum detection efficiency over a large spectral range. • small probability of generating noise. • the time between detection of a photon and generation of an electrical signal should be as constant as possible, i.e., the time jitter should be small, to ensure good timing resolution, • the recovery time (i.e., the dead time) should be short to allow high data rates.
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Absolute calibration technique for photon number resolving detectors
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Geiger Mode:
Active quenching
Problem: • Afterpulsing • Dark Counts
Si - detector quantum efficiency Some commercial SPAD
InGaAs - detector quantum efficiency
Absolute calibration technique for photon number resolving detectors
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Single Photon Avalance Diode (SPAD) Transition Edge Sensor (TES)
Photon number resolving High quantum efficiency ~ 99% Dead time: ~ 1 μ𝑠 Jitter time: ~ 100 ns Tens mK operating temperature Large dimensions
Not photon number resolving Low quantum efficiency < 60% Dead time: 30 ns – 10 ms Jitter time: 500 ps – 40 ps Room operating temperature Little dimensions
Introduction
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Single photons on demand
Heralded single photons
Thermal light Choerent light
Introduction
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Hanbury-Brown–Twiss experiment
Classical light
Quantum light
Absolute calibration technique for photon number resolving detectors
Hamiltonian
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Absolute calibration technique for photon number resolving detectors
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𝑘0 = 𝜂0(𝜃0, 𝜙0)𝜔0𝑐 𝑠
𝑘𝑠 = 𝜂𝑠(𝜃𝑠, 𝜙𝑠 )𝜔𝑠𝑐 𝑠
𝑘𝑖 = 𝜂𝑖(𝜃𝑖 , 𝜙𝑖 )𝜔𝑖𝑐 𝑠
Type I:
Tipe II:
Absolute calibration technique for photon number resolving detectors
Photon source parameters: o Pulse length: 50 ns
o Repetition rate: 20 kHz
o Pump power: 100mW
o Pump wavelength: 404 nm
o Signal wavelength: 808 nm
o Idler wavelength: 808 nm
o NLC: type I, Beta Barium Borate (BBO) , 1mm lenght
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Absolute calibration technique for photon number resolving detectors
In absence of heralded photon:
Measures
In the presence of heralded photons
P(i) P (i)
ξ is the probability of having a true heralding count γ is the TES “total” quantum efficiency
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Absolute calibration technique for photon number resolving detectors
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absence of the heralded photon
presence of the heralded photon
Separable Schmidt modes of a non-separable state– Introduction
Separable Schmidt modes of a non-separable state
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Alessio Avella, Giorgio Brida, Maria Chekhova, Marco Genovese, Marco Gramegna and Alexander Shurupov.
Separable Schmidt modes of a non-separable state – Introduction
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Classical Information
Bit:
Quantum Information
Qubit:
Bloch sphere
Multiple qubit
Be
ll’s
stat
es
Separable Schmidt modes of a non-separable state – Introduction
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Phase space Frequency space
Separable Schmidt modes of a non-separable state – Theoretical aspect
|𝜓 = 𝑑𝜔𝑠 𝑑𝜔𝑖 𝐹 𝜔𝑠, 𝜔𝑖 𝑎𝑠† 𝜔𝑠 𝑎𝑖
† 𝜔𝑖 |𝑣𝑎𝑐
Two-photon state generated by SPDC from a short-pulsed pump:
The Two-Photon Spectral Amplitude (TPSA):
𝐹 𝜔𝑠, 𝜔𝑖 = |𝜓(𝜔0, 𝜔𝑠, 𝜔𝑖)|2𝐹0(𝜔0)
Pump spectrum: 𝐹 𝜔0 Phase matching function: 𝜓(𝜔0, 𝜔𝑠, 𝜔𝑖)
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Separable Schmidt modes of a non-separable state – Introduction
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Non factorizable TPSA Schmidt decomposition
Schmidt mode
Where:
Schmidt number Schmidt mode do not overlap in frequency
Separable Schmidt modes of a non-separable state – Experimental aspect
TPSA:
𝐹 𝜔𝑠, 𝜔𝑖 = |𝜓(𝜔0, 𝜔𝑠, 𝜔𝑖)|2𝐹0(𝜔0)
𝑘0 = 𝜂0(𝜃0, 𝜙0)𝜔0𝑐 𝑠
𝑘𝑠 = 𝜂𝑠(𝜃𝑠, 𝜙𝑠 )𝜔𝑠𝑐 𝑠
𝑘𝑖 = 𝜂𝑖(𝜃𝑖 , 𝜙𝑖 )𝜔𝑖𝑐 𝑠
Shaping pump spectrum 𝐹 𝜔0 : Setting crystal parameter: length , material, angles.
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Separable Schmidt modes of a non-separable state – Experimental aspect
Registering the distribution of coincidences between signal and idler photons as a function of frequencies selected by monocromators.
•Kim, Y.-H. and Grice, W. P., Opt. Lett. 30, 908 (2005). •Wasilewski, W., Wasylczyk, P., Kelenderski, P., Banasek, K., and Radzewicz, C., Opt. Lett. 31, 1130 (2006).
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Separable Schmidt modes of a non-separable state– Experimental aspect
Two-Photon Time Amplitude (TPTA): the probability amplitude to register a signal photon at time 𝑡𝑠 and an idler photon at time 𝑡𝑖.
𝜔𝑠 =
𝜔0
2+ Ω𝑠
𝜔𝑖 =𝜔0
2+ Ω𝑖
𝐹 (𝑡𝑠, 𝑡𝑖)∝ 𝑑Ω𝑠𝑑Ω𝑖 𝑒𝑖Ω𝑠𝑡 𝑒𝑖Ω𝑖𝑡𝐹 Ω𝑠, Ω𝑖
TPTA is the 2D Fourier transform of TPSA:
|𝐹 (𝑡𝑠, 𝑡𝑖)| 2
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Separable Schmidt modes of a non-separable state – Experimental aspect
𝐹′ (𝑡𝑠, 𝑡𝑖)∝ 𝑑Ω𝑠𝑑Ω𝑖 𝑒𝑖Ω𝑠𝑡 𝑒𝑖Ω𝑖𝑡𝐹′ Ω𝑠, Ω𝑖
In a dispersive medium (as an optical fiber of length l), each of the photon creation operators acquires a frequency-dependent phase that can be attributed to the TPSA.
𝐹 ′ 𝑡𝑠, 𝑡𝑖 ∝ 𝑒−𝑖
𝑡𝑠2
2𝑘𝑠′′𝑙 −𝑖
𝑡𝑖2
2𝑘𝑖′′𝑙𝐹 Ω𝑠, Ω𝑖
𝑘′′ : second-order derivatives of the dispersion law.
𝐹 Ω𝑠, Ω𝑖 ⟶ 𝐹′ Ω𝑠, Ω𝑖 = 𝐹 Ω𝑠 , Ω𝑖 𝑒−𝑖𝑙 𝑘𝑠
′′Ω𝑠2+𝑘𝑖
′′Ω𝑖2 /2
Ω𝑠 =
𝑡𝑠𝑘𝑠′′𝑙
Ω𝑖 =𝑡𝑖𝑘𝑖′′𝑙
•Baek, S. Y., Kwon, O., and Kim, Y.-H., Phys. Rev. A 78, 013816 (2008). •Brida, G., Caricato, V., Chekhova, M. V., Genovese, M., Gramegna, M., and Iskhakov, T. S Opt. Exp. 18 (12), (2010).
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Separable Schmidt modes of a non-separable state – Experimental aspect
Profile FWHM: 0.2 ns Profile FWHM: 2 nm
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Separable Schmidt modes of a non-separable state – Experimental aspect
Laser: mode-locking Ti-Sapphire, pulse's length: 100 fs, gaussian spectrum @ 800 nm bandwidth: 11 nm.
SHG: travelling wave Second Harmonic Generator, gaussian spectrum @ 400 nm bandwidth: 2.8 nm
Fabry-Perot Interferometer: air spacing of 100 μm
Non-linear Crystal: BBO or KDP crystals.
DM: dicroic mirror.
PBS: polarizing beam splitter.
Fiber: 1 km length, single mode , attenuation:<3,5dB=km@780nm.
SPAD: silicon based Single Photon Avalanche Diode, dead time: 78 ns, timing resolution 50 ps, quantum eciency at 800 nm: 15%.
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Separable Schmidt modes of a non-separable state – Results
BBO crystal Size: (5x5x10)mm collinear configuration θ0 = 42,4 deg.
KDP crystal Size: (10x10x10)mm collinear configuration θ0 = 67,8 deg.
Pump spectrum
Pump spectrum
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Theoretical TPSA
Measured TPSA
Separable Schmidt modes of a non-separable state – Conclusion
Developed a software to calculate spectral property of a two-photon
states.
Made a technique to engeneer the spectral property of a two-photon states.
Made a technique to measure the spectral property of a two-photon
states. Made some measure of TPSA of different states and compare them whit
theoretial prediction.
Made entangled state whit Discrete Schmidt modes in continuous variables.
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High degree of entanglement and non-locality – Introduction
High degree of entanglement and non-locality of a two-photon state
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F. Sciarrino, G. Vallone, G. Milani, A. Avella 1,2, J. Galinis, R. Machulka, A. M. Perego, K. Y. Spasibko, A. Allevi, M. Bondani and P. Mataloni 1) Istituto Nazionale di Ricerca Metrologica, Torino, Italy; 2) Dipartimento di Fisica, Universita degli Studi di Torino, Torino, Italy;
High degree of entanglement and non-locality – Introduction
A. Einstein, B. Podolsky, and N. Rosen, “Can quantum-mechanical description of physical reality be considered complete?” Phys. Rev. 47 777 (1935).
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High degree of entanglement and non-locality – Introduction
“On the Einstein Podolsky Rosen paradox”, J. S. Bell, Physics 1 195 (1965).
J. S. Bell
He providing a mathematical formulation of locality and realism and he showed specific cases where this would be inconsistent with the predictions of QM.
Bell’s inequalities concern measurements made by observers on pairs of particles that have interacted and then separated.
Many experiment violate Bell’s inequalities but no final test was done
Local hidden variable theory
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High degree of entanglement and non-locality – Theoretical aspect
CHSH Inequality
Local
Real
Complete two particles, two observers, Alice and Bob,
and two dichotomic observables
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High degree of entanglement and non-locality – Theoretical aspect
measured probabilities:
set of 16 projection measurements:
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High degree of entanglement and non-locality – Results
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we obtained CHSH inequality violation by more than 33 standard deviations.
High degree of entanglement and non-locality – Conclusion
Experiment using entangled photons.
Experiment using entangled atoms.
Close detection loophole
Spatial separation
Bell’s inequality violated
Close detection loophole
Spatial separation
Bell’s inequality violated
It is possible exclude HVT???
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Large violation of Bell inequalities – Introduction
Alessio Avella 1,2, Giorgio Brida 2, Marco Genovese 1, Marco Gramegna 1. 1) Istituto Nazionale di Ricerca Metrologica, Torino, Italy; 2) Dipartimento di Fisica, Universita degli Studi di Torino, Torino, Italy;
Violation of Bell’s inequality using Both continuous and discrete variable
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Large violation of Bell inequalities – Theoretical aspect
Fock rapresentation: Quadrature rapresentation:
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Large violation of Bell inequalities – Experiment
With θ = 0 With θ = π/2
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Large violation of Bell inequalities – Theoretical aspect
X measurement
N measurement
N > 0 a, b = −1
N = 0 a, b = 1
a, b = −1 a, b = 1 a, b = −1
-z z
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Conclusion
Self consistent, absolute calibration technique for photon number resolving detectors.
Measurement of high degree of entanglement and nonlocality of a two-photon state.
Separable Schmidt modes of a non-separable state
Homodyne detection and application to experiment about foundation of quantum meccanics.
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Conclusion
“Engineering of spectral properties of two-photon states”, poster presented at the conference “Inaugural Workshop on Quantum-Photonic Hardware” (Perth, Australia, 22-25 October 2012).
“Engineering of spectral properties of two-photon states”, contributed talk at the conference “IQIS 2012” (Padova, Italy, 26-28 September 2012).
“Engineering of spectral properties of two-photon states”, poster presented at the conference “Quantum 2012” (Torino, Italy, 20-26 May 2012).
“Engineering of spectral properties of two-photon states”, poster presented at the conference “SPIE Optical Engineering + Applications” (San Diego, United States, 12-16 August 2012).
Engineering of spectral properties of two-photon states”, contributed talk at the conference “Quantum Africa 2” (South Africa, 3-7 September 2012).
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Conclusion
• A. Avella, G. Brida, M. Chekhova, M. Genovese, M. Gramegna, M. Vieille-Grosjean, A. Shurupov; “Engineering of spectral properties of two-photon states, preliminary results” Proc. SPIE 8518, Quantum Communications and Quantum Imaging X, 851812 (2012).
• F. Sciarrino, G. Vallone, G. Milani, A. Avella, J. Galinis, R. Machulka, A. M. Perego, K. Y. Spasibko, A. Allevi, M. Bondani and P. Mataloni, "High degree of entanglement and nonlocality of a two-photon state generated at 532 nm" EPJ-ST 199, number 1 (2011).
• A. Avella, G. Brida, I. P. Degiovanni, M. Genovese, M. Gramegna, L. Lolli, E. Monticone, C. Portesi, M. Rajteri, M. L. Rastello, E. Taralli, P. Traina, and M. White, “Self consistent, absolute calibration technique for photon number resolving detectors," Opt. Express 19, 23249-23257 (2011).
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A. Avella, G. Brida, D. Carpentras, A. Cavanna, I. P. Degiovanni, et al. "Report on proof-of-principle implementations of novel QKD schemes performed at INRIM", Proc. SPIE 8542, Electro-Optical Remote Sensing, Photonic Technologies, and Applications VI, 85421N (2012). A. Avella, G. Brida, D. Carpentras, A. Cavanna, I.P. Degiovanni, M. Genovese, M. Gramegna, P. Traina; “Review on recent groundbreaking experiments on quantum communication with orthogonal states”, preprint arXiv:1206.1503 (2012). A. Avella, G. Brida, I. P. Degiovanni, M. Genovese, M. Gramegna, and P. Traina, “Experimental realization of Goldenberg — Vaidman QKD protocol”. Applied Sciences in Biomedical and Communication Technologies (ISABEL), 2010 3rd International Symposium on, 10.1109/ISABEL.2010.5702879 (2010). A. Avella, G. Brida, I.P. Degiovanni, M. Genovese, M. Gramegna, P. Traina; “Experimental quantum-cryptography scheme based on orthogonal states” Physical Review A 82 (6), 062309 (2010). A. Avella, G. Brida, I. P. Degiovanni, M. Genovese, M. Gramegna and P. Traina, "Experimental quantum cryptography scheme based on orthogonal states: preliminary results". Proc. SPIE 7702, 77020E (2010).