I've suggested (& published in 15 journal papers) a new theory called quantised inertia (or MiHsC) that assumes that inertia is caused by relativistic horizons damping quantum fields. It predicts galaxy rotation, cosmic acceleration & the emdrive without any dark stuff or adjustment.
My Plymouth University webpage is here, I've written a book called Physics from the Edge and I'm on twitter as @memcculloch

Thursday, 14 July 2016


It would be good to test MiHsC directly with an experiment. One proposal I made in a paper in 2013 (see reference) was to try to damp Unruh waves on one side of an object so that the Unruh waves that impact it on the other side push it along. The problem is that Unruh waves are lightyears long for normal low accelerations, and you'd have to accelerate/spin a disc very fast to make Unruh waves short enough so they can be damped by standard technology. Accelerating heavy discs is problematic.

Since then I've shown that MiHsC seems to predict the emdrive fairly well, and this implies that MiHsC also modifies the collective inertial mass of photons (McCulloch, 2016). The logical conclusion is, instead of using heavy discs, why not rotate light in a similar way? The method would be as follows: put photons into a fibre-optic loop (see the white loop in the diagram) and put a metal baffle on one side (the grey rectangle).

The photons will circle around the loop at light speed so that their acceleration will be huge and the Unruh waves they see will be of a similar size to the loop, and their electromagnetic component might therefore be damped by putting a metal shield on the left of the loop (the grey rectangle). That means there will be more Unruh waves hitting the fibre-optic loop from the right (more orange colour) than from the left (less orange) so the loop should move left. It rolls down a gradient in the Unruh radiation field.

I've done a simple calculation, and shown that if 2 Watts of power is put into the loop as photons, and if the loop has a Q factor of 10^6 then the thrust should be something like 21 mN multiplied by the efficiency of the damper in damping Unruh radiation (which I do not know, but the emdrive suggests might be close to one). This would be a kind of emdrive using light, not microwaves. A LEMdrive?


McCulloch, M.E., 2013. Inertia from a asymmetric Casimir effect, EPL, 101, 59001. Preprint

McCulloch, M.E., 2016. Testing quantised inertia on the emdrive. EPL, 111, 60005. Preprint

Monday, 4 July 2016

MiHsC and Gravity from Uncertainty?

I've always liked Heisenberg's uncertainty principle, and a few years back I managed to derive something that looks like gravity from it (see references). This approach is very appealing: it feels somehow like the open channel, and over the weekend I managed to derive something that looks like MiHsC inertia from it (with caveats, see below). I won't go into details before publication, but to explain vaguely: the uncertainty principle says that the uncertainty in momentum of an object (Dp=D(mv)) times the uncertainty in position of it (Dx) is equal to the reduced Planck's constant (hbar), see the equation in the diagram:

This is pure quantum mechanics, but what happens if now we apply it on the macroscale where it is not supposed to be valid, and add relativity? When any object (the blue arrows in the diagram) accelerates, say, to the left (black arrows), a relativistic Rindler horizon forms to the right (the black curves) and blocks a huge chunk of space since information can no longer get from beyond that horizon to the object. With greater acceleration the horizon comes closer (see the diagram). Why not say that this horizon reduces the uncertainty of position, Dx? (the red arrows). It obviously does since the 'knowable space' shrinks. If we assume that and apply the uncertainty principle, then the momentum (or energy/c) uncertainty goes up and this becomes available to produce the inertial force to oppose the original acceleration (blue arrows).

I did the maths over the weekend, and the inertial mass predicted this way looks like that predicted by MiHsC (which explains galaxy rotation without dark matter and cosmic acceleration.. etc) My previous derivations are actually equivalent, but this way is rather elegant. There is a 27% difference though, which can be explained by the crudity of the model I've used so far: I have assumed the horizon is spherical.

What is becoming clearer is that MiHsC is inevitable if you take seriously both relativity and quantum mechanics, and allow an interaction between them on large scales.


McCulloch, M.E., 2014. Gravity from the uncertainty principle. Astrophys. and Space Sci., 349, 957-959.