27,682 reputation
455126
bio website www3.imperial.ac.uk/…
location London, United Kingdom
age 27
visits member for 3 years, 1 month
seen 55 mins ago

I'm a PhD student at the CDT in Controlled Quantum Dynamics at Imperial College London. My research is on strong-field and ultrafast physics, and I mostly study tunnel ionization and high-harmonic generation.

Check out my papers - they're nice!

You can also check out my Master's dissertation, "Under-the-barrier electron-ion interactions during tunnel ionization" at arXiv:1307.7329 or on my CDT homepage.

I did my Bachelor's degree in Physics in Mexico at the Faculty of Science at the Universidad Nacional Autónoma de México (UNAM). I studied quantum optics for my dissertation with Eduardo Nahmad Achar, and I have some nice results on the Jordan-block structure of the annihilation operator (as well as what became the J Phys A paper). You can find it (in Spanish) in the UNAM thesis repository.


1h
comment Doppler cooling limit vs recoil limit
No, that is not the case. In general absorbing a photon will tend to increase the kinetic energy of the atom and therefore heat it up. Only in very specific situations does laser light allow one to cool atoms (specifically, if one can engineer a way for atoms to absorb at one energy and emit a higher-energy photon, so they lose energy in the process). It sounds like you need to read a primer on laser cooling - try e.g. Wikipedia. Beyond that, ask a new question with the particular concepts you're having trouble with.
1h
comment Doppler cooling limit vs recoil limit
I'm not sure what the question is - I've explained it here already. If you have something more specific, do post it as a separate question.
2h
comment Emdrive in relation to newest NASA article - Does it extract energy out of the QM vacuum?
@brightmagus Not really. String theory is consistent with all current observations and the theories which we know are right (i.e. not speculative). The EmDrive is not: it breaks the conservation of momentum and of centre of energy, and it makes no theoretical attempt to explain why or replace the theory around it. There is at present no empirical evidence strong enough to discard the translation invariance of physical law, which rules out the EmDrive but not string theory.
3h
comment Emdrive in relation to newest NASA article - Does it extract energy out of the QM vacuum?
@pZombie My previous comment was indeed inaccurate - it seems NASA has allowed publications from Eagleworks (to my surprise). Nevertheless, until there are peer-reviewed tests performed in vacuum, "assuming it works" remains counterfactual physics (or speculative at best) and therefore off-topic. Further, please do not confuse statements on NASASpaceflight as official NASA articles, as your title suggests - there is no connection between the two.
3h
comment What are the proposed theoretical explanations for the EmDrive?
No worries. Good catch on the language there.
3h
comment What are the proposed theoretical explanations for the EmDrive?
Related meta discussion.
3h
comment What are the proposed theoretical explanations for the EmDrive?
@Kyle I have clarified the claim. I only mean that statement to apply to tests in vacuum.
3h
revised What are the proposed theoretical explanations for the EmDrive?
added 11 characters in body
3h
asked What are the proposed theoretical explanations for the EmDrive?
3h
answered What are the proposed theoretical explanations for the EmDrive?
8h
revised How to calculate meters per second speed when i have distance in meters and time in minutes
edited tags
8h
comment NASA's “Impossible” Space Engine
Related: Is the EmDrive, or “Relativity Drive” possible? and NASA's “Impossible” Space Engine and their many duplicates.
8h
comment Emdrive in relation to newest NASA article - Does it extract energy out of the QM vacuum?
Note that NASASpaceflight.com has no official relation with NASA itself. Until and unless NASA releases an official technical report endorsing these experimental findings, the NASA-related evidence for the EMdrive is simply: "there's this engineer who tested it in his living room and says it works". "Assuming that it works" is essentially counterfactual physics and therefore off-topic for this site. For more information, see this question and its many duplicates on the Linked sidebar.
11h
comment Does the definition of the SI unit “second” require that possible perturbation of primary frequency standards should be measured?
Simply put, I expect you to do your due diligence and check whether I have edited my answer when I say I have. I responded on the OP because, for reasons best known to yourself, you chose to reply to my answer there. That said, please keep the discussion to the point, and about the physics.
11h
comment Is it possible to speak about changes in a physical constant which is not dimensionless?
That is completely unclear. Perhaps you can provide some examples? Note in particular that "model dependent" and "incidental" depend on the set of assumptions you make about the world. (As an example, you can only set $c=1$ if you have solid empirical evidence that the speed of light is constant and independent of e.g. the relative speed of the source and the detector.) This is explored in detail in the references in my answer - please do read them thoroughly.
21h
comment Do rainbows have ultraviolet bands and infrared bands?
John, your post sort of makes it sound like aphakia is something I might want to have. This is in contrast with the Wikipedia page which makes it evident that I don't. Good find, by the way.
22h
comment Does the definition of the SI unit “second” require that possible perturbation of primary frequency standards should be measured?
Yes, that was intentional. Where else would I have posted an edit that I would expect you to have seen? This is the kind of thing that makes you come across as abrasive, by the way. Take your time if you need to.
22h
comment Does the definition of the SI unit “second” require that possible perturbation of primary frequency standards should be measured?
Metrological labs implement the standards as stated and measure the quality of their results in terms of fractional stability and little else. If you have a proposal for a standard which will implement MW ideal clocks and produce fractional stabilities on the order of $10^{-18}$ needed for modern science, by all means publish it!
22h
comment Does the definition of the SI unit “second” require that possible perturbation of primary frequency standards should be measured?
You can keep ignoring my edit if you want - as you have with every practical aspect of this discussion. As I explain below, precisely because it makes no appeal whatsoever to 'rods and clocks of atomic constitution', it has very little bearing on the devices that can actually be built.
23h
comment Does the definition of the SI unit “second” require that possible perturbation of primary frequency standards should be measured?
Well, take this as a heads-up: you come across as abrasive and entitled. Similarly, I suggest you use your disappointment for something constructive like adding a clear description of Marzke-Wheeler clocks to Wikipedia. In the meantime, I will go back to quietly mourning the fact that systematic errors are apparently no longer part of physics university and high-school curriculums (and yet the graduates feel qualified to demand that everyone else 'better be fully conversant' in pretty obtuse parts of relativity).