Quantum Mechanics and The Big World

Jasper van Wezel

Quantum Mechanics is one of the most successful physical theories of the last century. It explains physicalphenomena from the smallest to the largest lengthscales. Despite this triumph, quantum mechanics is often perceived as a mysterious theory, involving superposition states that are alien to our everyday Big World.In Quantum Mechanics and The Big World the connection between Quantum Mechanics and the Classical World, which we see around us every day, is investigated. The quantum origin of large systems turns out to continuously influence their behaviour. One of the consequences discussed in this thesis, is that qubits (the basic building blocks of a future quantum computer) can hold on to their stored quantum information only for a given time. After that time the qubit will be effectively reduced to just an ordinary bit.Another important connection between quantum mechanics and classical physics is the way in which gravity could influence quantum mechanical particles. In this thesis one particular idea about this influence is proposed.

Luis de la Peña, Ana Marı́a Cetto

J. van Wezel

Quantum Mechanics is one of the most successful physical theories of the last century. It explains physical phenomena from the smallest to the largest lengthscales. Despite this triumph, quantum mechanics is often perceived as a mysterious theory, involving superposition states that are alien to our everyday Big World. The construction of a future quantum computer relies on our ability to manipulate quantum superposition states in qubits. In this thesis it is shown that these qubits can be subtly influenced by the physics associated with spontaneous symmetry breaking. This process destroys the quantum nature of the qubit and renders it useless for quantum computation. An even more fundamental problem with quantum superpositions is that they cannot be reconciled with the theory of general relativity. In the end of this thesis a model is proposed which describes the effective, deteriorating, influence of gravity on quantum states, thus suggesting a path toward the demise of quantum mechanics in the big world.

Martin C. Gutzwiller

Jasper van Wezel

Quantum Mechanics is one of the most successful physical theories of the last century. It explains physical phenomena from the smallest to the largest lengthscales. Despite this triumph, quantum mechanics is often perceived as a mysterious theory, involving superposition states that are alien to our everyday Big World. The construction of a future quantum computer relies on our ability to manipulate quantum superposition states in qubits. In this thesis it is shown that these qubits can be subtly influenced by the physics associated with spontaneous symmetry breaking. This process destroys the quantum nature of the qubit and renders it useless for quantum computation. An even more fundamental problem with quantum superpositions is that they cannot be reconciled with the theory of general relativity. In the end of this thesis a model is proposed which describes the effective, deteriorating, influence of gravity on quantum states, thus suggesting a path toward the demise of quantum mechanics in the big world.

Bryce Seligman DeWitt