Security proof of coherent state and squeezed state CV protocols for bare CVQKD system: What's the measure of security and so what's the absolute secure case (criterion)? How to prove the absolute security of squeezed state and coherent state protocol using a general approach? What are the equivalence between coherent state (GG02 protocol) and squeezed state (xxx protocol) protocol? How about some other extended protocols?
Security proof of post-processing protocols for total CVQKD system: Error correction: Direct xxx, Reverse xxx; Privacy amplification
Relations among: secure key rate vs. secure transmission distance vs
General (if possible and necessary) analysis on the ways of attacks: Individual attack: general model and detailed analysis? Collective attack: general model and detailed analysis? Coherent attack: general model and detailed analysis? Moreover, Gaussian attack. BTW, what is PNS attack?
Summary of several important protocols: GG02, squeezed state protocol, etc. (if any)
Summarize several VERY important literatures on this, e.g.: GG02, etc.
All the above discussions, analysis and calculations, etc., should be restricted to CV cases (phase and amplitude and consider its equivalence to two conjugate variables for squeezed state and c).
Several keywords: secure key rate; secure transmission distance; entropy (Shannon; von Neumann); inter-information; measure; measurement; degree of security; xxx
Photon statistics theory: For GG02 protocol, coherent state should be emphasized and how to characterize the field state for the lasers; Photon statistics of the light field emitted by diode lasers: quantum open system theory for lasers; Several important photon distributions: Poissonian; Gaussian; Fock; thermal; Random number generation theory and implementation of random number generator.
Stochastic process theory: General theory of stochastic process and the basic concepts therein; Stochastic Schroedinger equation, Langevin equation and master equations for quantum open system; General theory of quantum noise and quantum detection; Several quantum detections: homodyne detection; heterdyne detection; QND detection, etc.
What are the key technical problems?
Laser source generation: DFB pulsed lasers: gain-switching and gain-switched; Any other kinds of lasers which can emit the coherent state; Variable attenuation and attenuator: several hundreds of photons inside;
Optics: Polarization maintained components; Local oscillator; Phase modulation and phase modulator; Amplitude modulation amplitude and modulator; Polarization maintainer (controller); Beam coupler (BC, c.f. BS) and polarization beam coupler (PBC c.f. PBS ); Atom filter; PAT; Atmosphere self-adaptor.
Quantum detection of signals: Homodyne detection using PIN; Heterdyne detection using PIN.
Post-processing software and hardware implementation: Error correction algorithms and software; Privacy amplification algorithm and software; LDPC coding algorithm and software.