When Photons Are Lying about Where They Have Been

Asking photons where they have been.

We present surprising experimental evidence regarding the past of photons passing through an interferometer. The information about the positions through which the photons pass in the interferometer is retrieved from modulations of the detected signal at the vibration frequencies of mirrors the photons bounce off. From the analysis we conclude that the past of the photons is not represented by c...

I-36: Preimplantation Genetic Diagnosis - Where Have We Been and Where Are We Going

Preimplantation genetic diagnosis (PGD) is now considered routine in IVF laboratories with micromanipulation capability and access to genetic diagnostic services. The past two decades have witnessed a dramatic increase in the use of PGD, the number of cycles performed, and the indications for which PGD has been used. This increase has been mirrored by a slow, but steady, increase in the range o...

Kinase inhibitors in rheumatoid arthritis: where have they been and where are they going?

Response: Commentary: “Asking photons where they have been” - without telling them what to say

Citation: Danan A, Farfurnik D, Bar-Ad S and Vaidman L (2015) Response: Commentary: " Asking photons where they have been "-without telling them what to say. A commentary on Commentary: " Asking photons where they have been "-without telling them what to say In a recent Commentary, Salih [1] claims that we " devised an elegant experiment investigating the past of photons inside two Mach-Zehnder...

Commentary: “Asking photons where they have been” - without telling them what to say

In a recent letter, Danan et al. [1] devised an elegant experiment investigating the past of photons inside two Mach-Zehnder interferometers, one inside the other—yet drew the wrong conclusions. Namely, that—based on weak measurements on preand post-selected states—some photons have been inside the inner interferometer but they never entered and never left. And, consequently, a “common sense” a...