A unified time analysis of photon and nonrelativistic particle tunnellings is presented, in
which time is regarded as a quantum observable, canonically conjugated to energy. Within …

In this article, after a theoretical introduction and a sketch of some related long-standing
predictions, a bird's-eye view is presented—with the help of nine figures—of the various …

One consequence of the special theory of relativity is that no signal can cause an effect
outside the source light cone, the space-time surface on which light rays emanate from the …

Recent research has estabHshed that it is possible to exercise extraordinary control of the
velocity of propagation of light pulses through a material system. Both extremely slow …

Publisher Summary Measurements of tunneling times by photons possess certain
advantages over those by electrons or other particles, stemming from the fact that the …

We present a simple electronic circuit which provides negative group delays for band-limited
baseband pulses. It is shown that large time advancement comparable to the pulsewidth can …

This paper deals with the similitude between the behaviours of linear filter gain and negative
group delay (NGD) function. The transposition method of low‐pass/high‐pass, low …

A comprehensive method to synthesize negative group delay (NGD) in the microwave
regime with a maximally flat response is proposed in this paper. This method is based on …

A fundamental theory of coupled line coupler-based negative group delay (NGD) topology is
established in this paper. The microwave circuit under study consists of the isolated-and …

The causality principle does not forbid negative group delays of analytic signals in electronic
circuits; in particular, the peak of a pulse can leave the exit port of a circuit before it enters …