User John Parker

6 votes

1 answer

857 views

What's the role of mixer in QAOA?

asked May 18, 2021 at 22:33

6 votes

1 answer

314 views

What is the "no fast-forwarding theorem"?

algorithm

asked Jul 13, 2021 at 1:17

5 votes

2 answers

244 views

What is the difference between amplitude amplification, amplitude estimation, and phase estimation?

algorithm phase-estimation amplitude-amplification

asked Jun 4, 2021 at 1:42

5 votes

1 answer

216 views

Oblivious Amplitude Amplification & Eigenstate decomposition

algorithm

asked Sep 28, 2021 at 14:12

5 votes

1 answer

91 views

Why does Hamiltonian simulation seek to find the energy minimum, if eigenvalues of unitaries are always unimodular?

algorithm hamiltonian-simulation phase-estimation

asked Oct 27, 2021 at 13:41

4 votes

1 answer

146 views

What is a simple example showing the issues of not doing the "uncomputation" step?

algorithm quantum-circuit

asked Jan 29 at 20:11

4 votes

0 answers

62 views

Implementing "computable phase shifts" using T Toffoli ( problem 4.1 from Nielsen and Chuang's)

textbook-and-exercises nielsen-and-chuang

asked Feb 1 at 21:38

4 votes

1 answer

396 views

What are spin-coherent states?

quantum-state quantum-optics angular-momentum

asked May 17, 2021 at 21:08

4 votes

1 answer

177 views

Variational Quantum Linear Solver (Hadamard test): circuit question

algorithm vqe linear-algebra

asked Jun 24, 2021 at 15:29

3 votes

2 answers

49 views

Normalization question in VQLS

qiskit algorithm textbook-and-exercises linear-algebra

asked Aug 25, 2021 at 11:22

3 votes

1 answer

395 views

How does the performance of QAOA and VQE compare to Grover's?

grovers-algorithm vqe qaoa

asked Jun 7, 2021 at 23:22

3 votes

1 answer

199 views

What is the relation between Hadamard transformation and QFT?

algorithm quantum-fourier-transform hadamard

asked Jun 4, 2021 at 14:04

3 votes

1 answer

118 views

Why are all the eigenvalues of a "Hermitian block-encoding" equal to $\pm1$?

algorithm unitarity eigenvalue

asked Sep 22, 2021 at 19:51

2 votes

1 answer

68 views

In block encoding, how to determine the dimension of the elements from $\alpha(⟨0|^{\otimes a}\otimes I)U(|0〉^{\otimes a}\otimes|\psi〉)=A|\psi〉$?

algorithm

asked Sep 14, 2021 at 20:01

2 votes

0 answers

19 views

contraction related Bit flip channel

information-theory

asked May 19 at 2:01

2 votes

1 answer

68 views

Manipulating the amplitude of state based on the state information

algorithm unitarity amplitude-amplification

asked Jun 14, 2021 at 17:37

2 votes

2 answers

121 views

How does a Hadamard discrete-time quantum walk result in a skewed distribution?

hadamard quantum-walks

asked Jun 18, 2021 at 17:42

2 votes

3 answers

498 views

Why does the trace of density operators need to be one?

quantum-state textbook-and-exercises density-matrix trace

asked Apr 6, 2021 at 17:37

2 votes

1 answer

200 views

Initial state preparation for Hadamard test

quantum-circuit hadamard

asked Jul 26, 2021 at 14:34

2 votes

0 answers

38 views

What's the importance of a relationship with Gibbs state in the context of VarQITE or variational algorithms?

algorithm vqe

asked Aug 8, 2021 at 12:12

1 vote

1 answer

147 views

Wick rotation of the Schrödinger equation

algorithm mathematics hamiltonian-simulation

asked Sep 10, 2021 at 17:56

1 vote

0 answers

42 views

Quantum Boltzmann Machine and Gibbs state

algorithm machine-learning quantum-enhanced-machine-learning

asked Jul 19, 2021 at 11:18

1 vote

1 answer

48 views

References about deriving the complexity of a given algorithm

algorithm resource-request complexity-theory

asked Sep 17, 2021 at 18:02

0 votes

0 answers

24 views

Matrix derivation from prepare+ /select/prepare operator

algorithm

asked Sep 23, 2021 at 18:27

0 votes

0 answers

36 views

Partial trace formulation

textbook-and-exercises partial-trace

asked Jan 23 at 20:54

0 votes

1 answer

35 views

In the context of block-encoding, what does $|0\rangle\otimes I$ represent?

mathematics linear-algebra

asked Jun 30, 2021 at 2:26

0 votes

1 answer

45 views

Trace calculation from the basis to |+> and |-> states

algorithm trace

asked Aug 18, 2021 at 14:37

0 votes

1 answer

89 views

In the amplitude amplification algorithm in Nielsen and Chuang's book, why is the error probability $M/N$?

textbook-and-exercises grovers-algorithm nielsen-and-chuang amplitude-amplification

asked Jun 4, 2021 at 19:32

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28 Questions

What's the role of mixer in QAOA?

What is the "no fast-forwarding theorem"?

What is the difference between amplitude amplification, amplitude estimation, and phase estimation?

Oblivious Amplitude Amplification & Eigenstate decomposition

Why does Hamiltonian simulation seek to find the energy minimum, if eigenvalues of unitaries are always unimodular?

What is a simple example showing the issues of not doing the "uncomputation" step?

Implementing "computable phase shifts" using T Toffoli ( problem 4.1 from Nielsen and Chuang's)

What are spin-coherent states?

Variational Quantum Linear Solver (Hadamard test): circuit question

Normalization question in VQLS

How does the performance of QAOA and VQE compare to Grover's?

What is the relation between Hadamard transformation and QFT?

Why are all the eigenvalues of a "Hermitian block-encoding" equal to $\pm1$?

In block encoding, how to determine the dimension of the elements from $\alpha(⟨0|^{\otimes a}\otimes I)U(|0〉^{\otimes a}\otimes|\psi〉)=A|\psi〉$?

contraction related Bit flip channel

Manipulating the amplitude of state based on the state information

How does a Hadamard discrete-time quantum walk result in a skewed distribution?

Why does the trace of density operators need to be one?

Initial state preparation for Hadamard test

What's the importance of a relationship with Gibbs state in the context of VarQITE or variational algorithms?

Wick rotation of the Schrödinger equation

Quantum Boltzmann Machine and Gibbs state

References about deriving the complexity of a given algorithm

Matrix derivation from prepare+ /select/prepare operator

Partial trace formulation

In the context of block-encoding, what does $|0\rangle\otimes I$ represent?

Trace calculation from the basis to |+> and |-> states

In the amplitude amplification algorithm in Nielsen and Chuang's book, why is the error probability $M/N$?