The Golden Trident

By Morgan Cranford

The Law of Conservation of Quantum Information tells us that quantum information, the information that is carried by microparticles, such as electrons or photons, in a data processing environment, cannot be created nor destroyed. This concept is fundamental to quantum mechanics and explains that information on the quantum scale (atoms, particles) doesn’t behave the same way that it does in the world of classical physics where information can be deleted and copied without issue. Quantum computing takes advantage of these strange properties in order to manipulate information in ways that classical computers can’t, but these properties also allow for a deeper understanding of the way information behaves in our universe. 

Black holes remove from our universe anything that passes their event horizon, which can be thought of as sort of a point of no return for matter and energy circling the black hole. Once this happens though, that matter and energy isn’t erased from our existence, it adds to the mass of the black hole. The same goes for quantum information passing the event horizon. In theory, the information should persist inside the black hole for as long as it continues to exist. 

As proven by Stephen Hawking in 1974, black holes will eventually, after incomprehensibly long periods of time, entirely evaporate into what is known as Hawking Radiation. Hawking Radiation is a type of electromagnetic radiation that contains only a fraction of the information originally captured by the black hole and escapes to just outside the event horizon, disproving the idea that nothing can escape a black hole once past the event horizon. Hawking Radiation, while merely theoretical because it has not been tested in a verifiable way, is generally accepted because the math tells us that it must be so. But because the information released in Hawking Radiation is not equivalent to the information that went into the black hole, we have ourselves a paradox. 

Our universe is made up of fields that in the presence of a super massive object like a black hole, get distorted or affected. In quantum mechanics, pairs of particles and antiparticles can spontaneously form out of seemingly empty space and then typically will remove each other from existence. Sometimes though, these particles will separate and one of them will fall into the black hole and the other will escape as what we know to be Hawking Radiation. The problem with this though is that energy cannot just appear out of nowhere and so it must be the case that the energy is coming from inside of the black hole. This theoretical process relies on our understanding of Quantum Field Theory and how quantum fields react with curved spacetime. With the understanding that a black hole must eventually completely evaporate into nothingness, the Hawking Radiation that escapes should, in theory, contain an equal amount of information that was contributing to the mass of the black hole. 

This is what is known as the Information Paradox and it defies our current understanding of quantum mechanics because it offers no explanation of where the information goes. We know that it cannot be created or destroyed; Stephen Hawking proves this. But what we don’t know is where the information goes after passing the event horizon of the black hole. This problem breaks our current understanding of quantum mechanics and if we assume that both general relativity and quantum field theory are correct then Hawking Radiation must both exist and erase quantum information, an idea that based on our understanding of everything, cannot happen. 

But, there’s no such thing as a true paradox. While we are limited with our knowledge of the universe right now, that doesn’t mean that something seemingly magical and inexplicable isn’t going on. We may never be able to understand it, but there must be a scientific explanation that solves the black hole information paradox. Near black holes, both gravity and quantum mechanics are happening, however each phenomenon is not well understood within a single mathematical framework.  This essentially “breaks the math” because gravity doesn’t fit within our current understanding of Quantum Field Theory (this is what physicists refer to as the “singularity” of the black hole). There is so much that we currently don’t and may never understand about the nature of black holes and the Information Paradox is just one of many things that doesn’t make any sense.