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![](/common/images/spacer.gif) Partial Trace of a Multiqubit System
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Organization: | Queen's Quantum Technology Group |
Department: | Dept. of Applied Mathematics and Theoretical Physics |
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![](/common/images/spacer.gif) 2005-02-24
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![](/common/images/spacer.gif) For many situations in Quantum Information Theory it is necessary to trace out a subgroup of qubits from a larger group. For example, suppose Alice, Bob and Charlie each have a qubit with the total system described by a density matrix. If we would like to examine more closely the subsystem of qubits shared by just Alice and Bob we need to take the trace. However for large multi-qubit systems, calculating this by hand becomes quite unmanageable. What the TraceSystem function does, is allow you to trace out an arbitrary number of qubits from a large system of N-qubits by getting Mathematica do the work for you.
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![](/common/images/spacer.gif) Quantum Information, Density matrix, Trace, Partial Trace, Multi-qubit system, Multiqubit system, Qubit, Multi
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| DensityTrace.nb (48 KB) - Mathematica Notebook [for Mathematica 5.0] |
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