Physics

Negative mass particles forged in new laser device

Negative mass particles forged...
An illustration of a device that can create particles with negative mass, thanks to an atomically thin semiconductor material placed inside the optical microcavity of a laser
An illustration of a device that can create particles with negative mass, thanks to an atomically thin semiconductor material placed inside the optical microcavity of a laser
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An illustration of a device that can create particles with negative mass, thanks to an atomically thin semiconductor material placed inside the optical microcavity of a laser
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An illustration of a device that can create particles with negative mass, thanks to an atomically thin semiconductor material placed inside the optical microcavity of a laser

In our everyday experience, if you push something, it moves away from you. But objects with negative mass would turn that basic principle on its head and accelerate towards you instead. It sounds like science fiction but the idea is theoretically possible, and its effects have been observed in recent experiments. Now, scientists from the University of Rochester have developed a device that can create particles that exhibit negative mass.

Newton's Second Law of Motion says that the force on an object is equal to its inertial mass multiplied by its acceleration (F = ma). Normally all of those values are positive: applying positive force on an object with positive mass will result in positive acceleration, pushing the object forwards. But if an object has negative mass, the force becomes negative too, meaning the object will move in the opposite direction – essentially, pressing itself against your hand if you try to push it.

At least, that's the idea. Negative mass has mostly only been demonstrated in theoretical analyses, although an experiment last year manipulated rubidium atoms with lasers to create a fluid that acted like it had negative inertial mass. Now, the University of Rochester researchers say they've developed a device that can create particles exhibiting negative mass, by combining photons from laser light and excitons in a semiconductor.

The device is based on a laser, with a core difference. Normally, light is bounced between a pair of mirrors facing each other, and the space where that light is confined is called the optical cavity, or microcavity. In this device's optical microcavity, the team placed an atomically-thin semiconductor made of molybdenum diselenide, where it could interact with the confined light. Excitons in the semiconductor combined with photons in the confined laser light to form new particles called polaritons, which have negative mass.

"By causing an exciton to give up some of its identity to a photon to create a polariton, we end up with an object that has a negative mass associated with it," says Nick Vamivakas, lead author of a study describing the device. "That's kind of a mind-bending thing to think about, because if you try to push or pull it, it will go in the opposite direction from what your intuition would tell you."

The researchers are still working to explore the physics of negative mass particles in the device, and although practical applications are still a long way off, one of the first improvements could be more efficient lasers.

"We're dreaming up ways to apply pushes and pulls – maybe by applying an electrical field across the device – and then studying how these polaritons move around in the device under application of external force," says Vamivakas. "But it also turns out the device we've created presents a way to generate laser light with an incrementally small amount of power. With the polaritons we've created with this device, the prescription for getting a laser to operate is completely different. The system starts lasing at a much lower energy input."

The research was published in the journal Nature Optics.

Source: University of Rochester

10 comments
Lambert
This might be a part of a solution as where vacuum is created to move objects very fast in a 'vacuum freeway' without them heating and lighting up by the collision with molecules (movin in a direction). When under circumstances gravity can be seen as a wave (like Einstein predicted) , like anti-sound (producing exact counter-waves) creates slience, anti-gravity waves could create a mass of zero (in theory). Like to see the next steps. Kind regards Lambert.
notarichman
so how would this affect a space ship? assuming that some of the ship would have mass and some of it would have negative mass; then would you subtract the negative from the positive mass in computing the acceleration? same question for cars?
Bob
So does gravity, like light, behave like a wave and a particle??? Actually this phenomenon sounds more like try to get a teenager to do any useful work. The more you push or pull, the more resistance you get. Rename this the "teenage particle".
Chris74
sounds like manipulating the electomagnetic field around particles and not creating some fancy term called negative mass to be completely honest
notarichman
E = -MC^2 ???
The Creator
Great. Hopefully next they can figure out how to convert this negative mass to negative energy. Because according to some scientists, with negative energy, Warp drives and stable traversable wormholes should be possible.
AtillaDHunn
Paint the tail of your spaceship with it, hit it with a laser (from within) and you have anti-gravity drive.
john756
It is interesting that the force of gravity will collect two negative masses but repel opposite masses ( assuming we use Newton) F = GMm/R^2. If M and m have the same sign, its attractive force, if different, it repels. But does this also play with Thorne and Wheeler ( and Einstein)? What is the interaction with space? Until tested, like dark matter - will the path of light be deflected or attracted to this negative mass item?
sjbauer
The concept was previously presented in ‘The Evolutioning of Creation: Volume 2’, as ‘negative mass density’ as copyrighted in 2011. As the predominant condition of the universe is combination of dark matter and dark energy (i.e., massless matter and energy), then the existence of mass is more an intrusion upon this norm. Such is it that this displacement effect is expressed as if the mass has intruded upon its relative consistent, or inertial, condition of the Space-Time continuum.. This ground breaking book is set to be presented at the American Library Association Mid-Winter Gathering 2019 in Seattle, WA, from January 25-29, 2019.
john75
This raises so many questions. One being can this be used as a reaction less drive? If so even a very low thrust system could circumvent the rocket equation and achieve far higher delta-v than any reaction rocket, even nuclear thermal. Possibly even more than an Orion style craft riding the wake of atomic explosions. But closer to home how exactly does this work? From what I just read it almost sounds like if you wore shoes with this built in, the force of your own body weight pushing down on it would push you up in a standard Newtonian example of equal and opposite forces. That seems like you would be able to step out of a helicopter...at any altitude and simply stand in thin air. Just my impression?