7,814 research outputs found
On the "principle of the quantumness", the quantumness of Relativity, and the computational grand-unification
After reviewing recently suggested operational "principles of the
quantumness", I address the problem on whether Quantum Theory (QT) and Special
Relativity (SR) are unrelated theories, or instead, if the one implies the
other. I show how SR can be indeed derived from causality of QT, within the
computational paradigm "the universe is a huge quantum computer", reformulating
QFT as a Quantum-Computational Field Theory (QCFT). In QCFT SR emerges from the
fabric of the computational network, which also naturally embeds gauge
invariance. In this scheme even the quantization rule and the Planck constant
can in principle be derived as emergent from the underlying causal tapestry of
space-time. In this way QT remains the only theory operating the huge computer
of the universe. Is QCFT only a speculative tautology (theory as simulation of
reality), or does it have a scientific value? The answer will come from Occam's
razor, depending on the mathematical simplicity of QCFT. Here I will just start
scratching the surface of QCFT, analyzing simple field theories, including
Dirac's. The number of problems and unmotivated recipes that plague QFT
strongly motivates us to undertake the QCFT project, since QCFT makes all such
problems manifest, and forces a re-foundation of QFT.Comment: To be published on AIP Proceedings of Vaxjo conference. The ideas on
Quantum-Circuit Field Theory are more recent. V4 Largely improved, with new
interesting results and concepts. Dirac equation solve
Direct certification of a class of quantum simulations
One of the main challenges in the field of quantum simulation and computation
is to identify ways to certify the correct functioning of a device when a
classical efficient simulation is not available. Important cases are situations
in which one cannot classically calculate local expectation values of state
preparations efficiently. In this work, we develop weak-membership formulations
of the certification of ground state preparations. We provide a non-interactive
protocol for certifying ground states of frustration-free Hamiltonians based on
simple energy measurements of local Hamiltonian terms. This certification
protocol can be applied to classically intractable analog quantum simulations:
For example, using Feynman-Kitaev Hamiltonians, one can encode universal
quantum computation in such ground states. Moreover, our certification protocol
is applicable to ground states encodings of IQP circuits demonstration of
quantum supremacy. These can be certified efficiently when the error is
polynomially bounded.Comment: 10 pages, corrected a small error in Eqs. (2) and (5
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