Today, some media (sorry, spanish one), in small and without disturbing anyone, tell us that at Washington State University they have succeeded in creating a “negative mass”.
But what is a negative mass? Well, a negative mass is a mathematical concept in which, just as the mass has a positive value, it would have a negative value.
The biggest problem with this concept is that street people are only able to think about it in a gravitational way. That is, of the four fundamental forces, it only remains with one, gravity, without realizing that a negative mass violates the equations of the other three forces.
The concept of negative mass comes from the same idea as the process of electric charge. Just as there are positive and negative electric charges, it is thought, by mere mathematics, that there must be positive and negative mass. The problem is that electric charges, whether positive or negative, is based on having more or less electrons than protons, but in the mass, there are really no elements to give and others to take away.
Therefore, the idea is twisted and put the fabric of space time over indicating that although the mass is that which deforms the space time there is to be, that deformation inflation and deflation (that is, bulk down and bulk up).
The way in which these scientists think they have created negative mass is based on the Newtonian idea where $latex F = ma$ and that, applying an acceleration to a mass, being this negative, the force that is obtained goes in the opposite direction To which force is applied.
In order to do so, they have cooled rubidium atoms to Bose-Einstein cube levels (about 0K) and pushed them with a laser observing that they went in the opposite direction (as seen in the image).
The problem is that at these levels, the equations to be used are in the matter of quantum mechanics, and Schrödinger has no mass in his equations. Hence they have played tricks and have used the equations of Klein-Gordon where the mass appears.
Where h, in the above equation is the reduced Plank constant. And that allows us, the equation, positive values of kinetic energy and, therefore, that exists and is valid.
That is, these scientists have demonstrated that the mathematical application realized exists. But you have to be careful and careful until you do not corroborate.
I, of course, always point out that you go to the source (journals.aps.org) where you have the paper to take a look at.