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11441
bio website lac.u-psud.fr/…
location Paris, France
age 38
visits member for 3 years, 11 months
seen 20 hours ago

Researcher in quantum information, mainly on cryptography.


Oct
17
awarded  Good Answer
Oct
14
comment Has the gravitational interaction of antimatter ever been examined experimentally?
but the currently accepted theories suppose the effect to be 0 anyway, so the question whether the speed should cancel this already null effect is difficult to answer, except by experiment.
Oct
14
comment Has the gravitational interaction of antimatter ever been examined experimentally?
About ultrarelativistic effects : the work cited build upon other work showing that the gravitational effect on (anti)neutrinos are within 10⁻³ of the one on photons, because the neutrinos and photon were detected within a few hours.
Oct
10
comment Is it enough to use only sigma criterion to calculate expected value for ideal Bell's test experiment?
I guess you are describing the well known detection loophole : If the particles have three answers (±1, no event) and not two (±1), they can cheat by pretending not to be detected (and changing the number of events). If a fraction η of the particle lead to detection, S≤2 becomes S≤4/η - 2. Today (2014/10/10), no experiment has closed locality and detection loophole simultaneously.
Oct
10
answered Has the gravitational interaction of antimatter ever been examined experimentally?
Oct
10
revised Where does de Broglie wavelength $\lambda=h/p$ for massive particles come from?
Correct de Broglie orthography
Oct
10
comment Is it enough to use only sigma criterion to calculate expected value for ideal Bell's test experiment?
Your answer can be summed up in a few words : The S<2 bound is a bound on an expectation value on a statistical quantity, and is only valid with infinitely many measurement. The [law of large numbers](Law_of_large_numbers) (or the centrel limit theorem if you want to be more quantitative) guarantees that you cannot go to far above 2. That’s why the deviation is usually measured in units of σ : it is easy to compute, and it is (exponentially) related to the probability of a spurious coincidence.
Oct
9
comment What determines color — wavelength or frequency?
What I want to say seems very close : the frequency is fixed during the life of the photon, and determines the wavelength in the eyeball. The wavelength in the original medium is relevant only in so far that it is linked to the constant frequency of the photon. Anyway, it seems we agree on what happens physically and we only disagree on the best way to describe it, which is secondary.
Oct
9
answered How did phase randomly changed in CHSH test (M. A. Rowe and others)?
Oct
8
comment What determines color — wavelength or frequency?
The frequency is independent of the external n, and stays the same inside the eyeball. I have no idea whether the relevant quantity is the frequency or the wavelength inside the eyeball (or inside the cone cells). I don’t think the last sentence is wrong, but it is probably not clear. How would you formulate this idea ?
Sep
30
awarded  Explainer
Sep
9
answered Detection Angles in Bell-type Experiments
Jun
20
comment Is there a cheap way I can do a Bell inequality experiment?
The most expensive part will be the single-photon detectors (a few 1,000$). Then, you cannot use two lasers because the photon would not be entangled. You need an entangled photon source (usually a suatably pumped BBO crystal)
Jun
20
reviewed Close Does time really exist?
Jun
19
comment Why isn't the best case classical solution to the CHSH game 100%?
@DavidZ I feel strongly about it, so I posted a question on meta.
Jun
17
comment Why isn't the best case classical solution to the CHSH game 100%?
The CHSH game has been invented by physicists to study a physics question (nonlocality). If you don't like to speak about games, call it the CHSH thought experiment!
May
28
awarded  Populist
May
28
comment Continuous Variable Entanglement Measure for the Statistically Mixed State
By the way, a review on entanglement measures is here : arxiv.org/abs/quant-ph/0504163
May
28
comment Continuous Variable Entanglement Measure for the Statistically Mixed State
It depends what you call valid. Logarithmic negativity always detect free (i.e. distillable) entanglement. But in high dimension, you have bound (i.e. undistillable) entangled states. These are entangled state with 0 log-negativity. But log-negativity is not invalid, since a non-zero negativity really means there is some entanglement, even in high dimension. Finding a “valid” entanglement measure, (detecing all entangled states) is essentially hopeless, since the probleme of entanglement detection has been linked to th NP problem.
May
28
comment Continuous Variable Entanglement Measure for the Statistically Mixed State
But if you only want a simple to compute entanglement measure, (logarithmic) negativity is your friend