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# Quantum Phase Estimation and Hadamard test discussion#14

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opened this issue Jun 3, 2019 · 10 comments
Closed

# Quantum Phase Estimation and Hadamard test discussion #14

opened this issue Jun 3, 2019 · 10 comments

### vtomole commented Jun 3, 2019 • edited

 The text was updated successfully, but these errors were encountered:

### masaduzz1 commented Jul 30, 2020

 Hi, thanks for the nice post. In the example of the Hadamard test, the output expression of the CU applied on 2 qubits does not look correct.

### vtomole commented Jul 30, 2020

 Which part are you talking about exactly? Is it The Hadamard test solves: Given a Unitary .... part? What's not correct about it?

### masaduzz1 commented Jul 30, 2020

 Hi, thanks for the reply. When CU applied on (|0>+|1>) x |1>, isn't the o/p be |0>|1> + |1>(U|1>) = |0>|1> + |1>|0>? I didn't carry the 1/sqrt(2) factor here.

### vtomole commented Jul 31, 2020

 |0>|1> + |1>(U|1>) = |0>|1> + |1>|0> You have `U` on the left side but not the right. Where did it go?

### masaduzz1 commented Jul 31, 2020 via email

 I thought only the second qubit is modified if 1st qubit is 1 when two qubits are applied in the CU gate. Please see wiki here: https://en.wikipedia.org/wiki/Quantum_logic_gate#Controlled_(cX_cY_cZ)_gates Sincerely, Asaduzzaman … ________________________________ From: Victory Omole Sent: Friday, July 31, 2020 12:40 PM To: vtomole/vtomole.github.io Cc: Muhammad Asaduzzaman ; Comment Subject: Re: [vtomole/vtomole.github.io] Quantum Phase Estimation and Hadamard test discussion (#14) |0>|1> + |1>(U|1>) = |0>|1> + |1>|0> You have U on the left side but not the right. Where did it go? — You are receiving this because you commented. Reply to this email directly, view it on GitHub<#14 (comment)>, or unsubscribe.

### vtomole commented Jul 31, 2020

 You wrote |0>|1> + |1>(U|1>) = |0>|1> + |1>|0> What is `U` here? Is it an arbitrary unitary or did you make it the X gate?

### masaduzz1 commented Jul 31, 2020 via email

 I was talking about the hadamard test example in your post, U there is (0, 1; 1, 0) … ________________________________ From: Victory Omole Sent: Friday, July 31, 2020 2:25 PM To: vtomole/vtomole.github.io Cc: Muhammad Asaduzzaman ; Comment Subject: Re: [vtomole/vtomole.github.io] Quantum Phase Estimation and Hadamard test discussion (#14) You wrote |0>|1> + |1>(U|1>) = |0>|1> + |1>|0> What is U here? Is it an arbitrary unitary or did you make it the X gate? — You are receiving this because you commented. Reply to this email directly, view it on GitHub<#14 (comment)>, or unsubscribe.

### vtomole commented Aug 1, 2020

 Ah okay. I see my mistake. Thanks for pointing this out. I'll post a fix soon.

### masaduzz1 commented Aug 1, 2020 via email

 great then, thank you. … ________________________________ From: Victory Omole Sent: Friday, July 31, 2020 9:42 PM To: vtomole/vtomole.github.io Cc: Muhammad Asaduzzaman ; Comment Subject: Re: [vtomole/vtomole.github.io] Quantum Phase Estimation and Hadamard test discussion (#14) Ah okay. I see my mistake. Thanks for pointing this out. I'll post a fix soon. — You are receiving this because you commented. Reply to this email directly, view it on GitHub<#14 (comment)>, or unsubscribe.

### vtomole commented Aug 6, 2020

 @masaduzz1 Hey, i made the fixes. Can you check to make sure that it makes sense now? Also, i would like to send you \$5 as a thank you for finding this. How should i go about this?

Repository owner locked and limited conversation to collaborators Jun 27, 2023
converted this issue into discussion #49 Jun 27, 2023

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