From 724c79fa5648382eb97dd39c2944f6e4ed84d84e Mon Sep 17 00:00:00 2001 From: Luke Devlin Date: Tue, 11 Aug 2026 21:49:17 +0100 Subject: [PATCH 1/2] Fix incorrect answer to Grover's algorithm understanding question --- learning/modules/computer-science/grovers.ipynb | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/learning/modules/computer-science/grovers.ipynb b/learning/modules/computer-science/grovers.ipynb index 3a769badb88..9e7c9e95535 100644 --- a/learning/modules/computer-science/grovers.ipynb +++ b/learning/modules/computer-science/grovers.ipynb @@ -174,7 +174,17 @@ "\n", "\n", "\n", - "When we apply X to the $|+\\rangle$ state, we get the value and +1 and to the state $|-\\rangle$ we get -1, so if we had a 50-50 distribution, we would get an expectation value of 0.\n", + "Starting from the gate definitions:\n", + "\n", + "$$H|0\\rangle = \\frac{1}{\\sqrt{2}}(|0\\rangle+|1\\rangle), \\qquad H|1\\rangle = \\frac{1}{\\sqrt{2}}(|0\\rangle-|1\\rangle)$$\n", + "\n", + "Apply $H$ a second time, using linearity:\n", + "\n", + "$$H\\left[\\frac{1}{\\sqrt{2}}(|0\\rangle+|1\\rangle)\\right] = \\frac{1}{\\sqrt{2}}\\left(H|0\\rangle+H|1\\rangle\\right) = \\frac{1}{2}\\left[(|0\\rangle+|1\\rangle)+(|0\\rangle-|1\\rangle)\\right] = |0\\rangle$$\n", + "\n", + "$$H\\left[\\frac{1}{\\sqrt{2}}(|0\\rangle-|1\\rangle)\\right] = \\frac{1}{\\sqrt{2}}\\left(H|0\\rangle-H|1\\rangle\\right) = \\frac{1}{2}\\left[(|0\\rangle+|1\\rangle)-(|0\\rangle-|1\\rangle)\\right] = |1\\rangle$$\n", + "\n", + "So $H(H|0\\rangle)=|0\\rangle$ and $H(H|1\\rangle)=|1\\rangle$, confirming $H^2=I$ as claimed above.\n", "\n", "\n", "\n", From bc519a9644083df29579ae214af1cf6238bb767b Mon Sep 17 00:00:00 2001 From: Luke Devlin Date: Tue, 11 Aug 2026 21:49:46 +0100 Subject: [PATCH 2/2] Add 'forall' to dictionary --- scripts/config/cspell/dictionaries/qiskit.txt | 1 + 1 file changed, 1 insertion(+) diff --git a/scripts/config/cspell/dictionaries/qiskit.txt b/scripts/config/cspell/dictionaries/qiskit.txt index f82d5392db3..34500f78350 100644 --- a/scripts/config/cspell/dictionaries/qiskit.txt +++ b/scripts/config/cspell/dictionaries/qiskit.txt @@ -53,6 +53,7 @@ expressibility Factorizers FCIDUMP Fieldr +forall Hadamard Hamiltonians IBMQPU