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FQXI ARTICLE

March 24, 2017

Collapsing Physics: Q&A with Catalina Oana Curceanu

Tests of a rival to quantum theory, taking place in the belly of the Gran Sasso d’Italia mountain, could reveal how the fuzzy subatomic realm of possibilities comes into sharp macroscopic focus.

FQXi Awardees: Catalina Oana Curceanu

June 24, 2016

Catalina Oana Curceanu

National Institute of Nuclear Physics, Frascati, Italy

The theory of quantum mechanics is very successful in describing the world and phenomena on a microscopic scale (electrons, atoms, and even molecules), but it starts to be questionable whether the same theory can describe macroscopic bodies, or aggregates of many, many atoms.

The superposition principle tells us that microscopic bodies can be in various possible states at the same time (Schrödinger’s famous cat is both dead and alive). This is described mathematically using a "wavefunction," which comes from solving an equation derived by Erwin Schrödinger. However, when one performs a measurement only one definite answer arrives (the cat is either dead or alive): the wavefunction has collapsed. This is the famous "measurement problem."

The question is then: how does the wavefunction collapse to generate the event we see? Our FQXi project deals with exactly this question.

We aim to measure signals from a theory that modifies the Schrödinger equation, adding terms that induce the collapse of the wavefunction in a very natural way. The specific model we use is the "continuous spontaneous localization" model. This has the nice feature that it allows microscopic systems to remain in superposition for a long time, while it immediately collapses the wavefunction of big bodies. This collapse is thought to be induced by the interaction of the particles with a special collapsing "field."

We might see

shadows of

a new physics.

shadows of

a new physics.

- Catalina Oana Curceanu

This emission is not present in standard quantum mechanics, but is a unique feature of the collapse model and we are trying to measure it.

This radiation is not due to some field that is known, but would appear to be a weird phenomenon in which energy does not seem to be conserved. Of course, in reality, energy is conserved, but we would need to know the theory "beyond standard quantum mechanics" to conserve it properly. A hypothesis is that this field could be related to the gravitational field.

We use an ultrapure germanium detector and measure the radiation emitted by the detector itself, searching for the spontaneous radiation emitted by the electrons as well as the protons of germanium atoms.

Quantum Tunneling

Will an experiment buried deep within the Gran Sasso d’Italia

mountain reveal that an alternative model of the subatomic

world is right?

We try to reduce the influence of cosmic radiation as much as possible, so we do our experiments in the belly of the Gran Sasso d’Italia mountain. The LNGS laboratory—three huge cathedral-like spaces in the mountain connected by galleries—is located half way in the 10km long tunnel that connects the cities of L’Aquila and Teramo. In the mountain, cosmic rays are reduced by a factor of a million with respect to ground experiments.

To reduce the background even further, we use ultra pure germanium instruments. However, there is still some radiation from the materials we use to perform our experiments and from the environment (as radon). So we use Monte Carlo simulations for data analyses to see which part of the X-ray spectrum we measure does not come from the collapse, but from radionuclides present in the setup materials.

We have done preliminary measurements and are now analysing the data. We are finding out what part of our signal can be ascribed to the residual background. Some very interesting results are coming out which we hope to publish soon.

Collapse models are characterised by the so-called "lambda-parameter," which describes the number of interactions of particles with the collapsing field per second. There are two limits proposed in theory. One is conservative (proposed by physicist GianCarlo Ghirardi at the University of Trieste, in Italy and others) in which lambda is 10

I believe there is a continued search for deeper understanding, but I don’t believe there is a theory of everything yet. It might also be that we are with quantum mechanics where Newton was with respect to Einstein. With the numerous experiments that are going on today, I hope we might get a hint of a new theory and I hope to contribute by performing nice experiments. It is also a lot of fun!

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DURGA DAS DATTA. wrote on July 8, 2016

Let us be very careful about classical and quantum concepts. Sometimes we talk of one such idea in quantum gravity which will also explain classical. The question of GR and its application in quantum is a huge problem Time ideas in both the theories does not match . We do not even know whether Einstein is correct in his GR approach. The fact of matter is gravity is not a potential or field of infinite range etc. Gravity is emergent due two types of gravitons. One is FERMION GRAVITON...

Let us be very careful about classical and quantum concepts. Sometimes we talk of one such idea in quantum gravity which will also explain classical. The question of GR and its application in quantum is a huge problem Time ideas in both the theories does not match . We do not even know whether Einstein is correct in his GR approach. The fact of matter is gravity is not a potential or field of infinite range etc. Gravity is emergent due two types of gravitons. One is FERMION GRAVITON...

STEVE DUFOURNY wrote on June 24, 2016

What are your geometrical algebras implying this ? Lie,Clifford,Magma,Hopf....Tell me I will show you your errors in all humility.I will share if you want my spherical algebras with the spherical volumes and p adics numbers correlated with the universal serie of spherical volume giving the serie of uniqueness.This is for the stable gravitational serien encoding ,not the particles produced by cosmological sphères of course.Nothing is easy and we know nothing still about our universe?THE...

What are your geometrical algebras implying this ? Lie,Clifford,Magma,Hopf....Tell me I will show you your errors in all humility.I will share if you want my spherical algebras with the spherical volumes and p adics numbers correlated with the universal serie of spherical volume giving the serie of uniqueness.This is for the stable gravitational serien encoding ,not the particles produced by cosmological sphères of course.Nothing is easy and we know nothing still about our universe?THE...

SKY LEACH wrote on June 24, 2016

@Joe Fisher

That's not quite accurate. You can't sum infinity, but you can describe set interactions at specific points without bounding the set itself. This gives behavior in regions.

@Joe Fisher

That's not quite accurate. You can't sum infinity, but you can describe set interactions at specific points without bounding the set itself. This gives behavior in regions.

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