Quantum Computing Stack Exchange
Quantum Computing Stack Exchange

Questions tagged [solid-state]

For questions regarding design, development or theory of solid-state devices as relevant to quantum computers. May also be used for questions regarding solid state physics or chemistry, if they are relevant to quantum computing.

17 questions
22
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3 answers

Is Quantum Biocomputing ahead of us?

Now that we know of bio/molecular tools that allow living organisms to deal with quantum computations e.g. the fancy proteins that allow birds to handle quantum coherence (e.g. The quantum needle of the avian magnetic compass or Double-Cone…
AG-M
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19
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2 answers

What's the Difference between T2 and T2*?

$T_2$ generally refers to the measurement of the coherence of the qubit with respect to its dephasing (that's a rotation through the $|0\rangle$ - $|1\rangle$ axis of the Bloch sphere for those of us visualizing). But sometime in the literature,…
psitae
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12
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0 answers

Active improving of nanodiamond surfaces for NV centers?

This question is related (and complementary) to "Passive improving of nanodiamond surfaces for NV centers?". Nitrogen-Vacancy centers (NVs) have astonishing quantum properties, which make them interesting as potential hardware both for quantum…
agaitaarino
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10
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0 answers

Entanglement transfer of spin-entangled triplet-pair states between flying qubits and stationary qubits

The context: We are in the solid state. After a photon absortion by a system with a singlet ground state, the system undergoes the spin-conserving fission of one spin singlet exciton into two spin triplet excitons (for context, see The entangled…
agaitaarino
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9
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1 answer

Decoherence of spin-entangled triplet-pair states in the solid state: local vs delocalized vibrations

The context: We are in the solid state. After a photon absortion by a system with a singlet ground state, the system undergoes the spin-conserving fission of one spin singlet exciton into two spin triplet excitons (for context, see The entangled…
agaitaarino
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8
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1 answer

Difference between coherence transfer, polarization transfer and population transfer?

I asked a question on Physics Stack Exchange but no one answered the question and I didn't get enough views on it. I am asking it on QCSE because the question is related to experimental quantum computation realized through NMR. For an ensemble of…
Jitendra
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8
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3 answers

If a Hamiltonian is quadratic in the ladder operator, why is its time evolution linear in the ladder operator?

How can one show that $\hat{U}^\dagger\hat{a}\hat{U}$ (with $\hat{U} =e^{-i\hat{H}t}$) involves only linear orders of the ladder operator, when $H$ is the general quadratic Hamiltonian $(\hat{H} = \alpha (\hat{a}^\dagger)^2+ \beta…
heromano
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7
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1 answer

Translation of color/toric code to a small network of solid-state spins

Within Quantum Error Correction and stabilizer codes, toric codes/surface codes are very tempting, mainly for their high error threshold. For more background please check up, in our Physics sister (aunt?) site: Quantum Error Correction: Surface code…
agaitaarino
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6
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1 answer

Do we know anything about the computational complexity of the exchange-correlation functional?

Density functional theory is based on the Hohenberg-Kohn (HK) theorems and aims to compute the ground-state many-body wavefunction of a physical material and/or molecules. To put it simply, the HK theorems show that there is a unique one-to-one…
Dr. T. Q. Bit
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5
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1 answer

Which temperature has been the highest to achieve a quantum logic operation?

My question is somehow related with a previous one: What is the most optimistic perspective of room-temperature solid-state QC?. Regarding solid-state qubits, What is the highest temperature at which the simplest quantum logic operation has been…
SalvaCardona
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5
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1 answer

Passive improving of nanodiamond surfaces for NV centers?

Nitrogen-Vacancy centers (NVs) have astonishing quantum properties, which make them interesting as potential hardware both for quantum computing in particular and for quantum technologies in general. In part this results from the center being…
agaitaarino
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5
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1 answer

What is the most optimistic perspective of room-temperature solid-state QC?

I've read the "trend" article entitled Is a room-temperature, solid-state quantum computer mere fantasy? from almost 10 years ago, and was wondering if things have really changed: What is the current consensus on the viability of a room-temperature…
Daniel Tordera
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4
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Do avoided crossings / CTs /ZEFOZs optimize quantum fidelity in practice?

CTs / ZEFOZs: Energy level structures that include avoided crossings at accessible energies tend to be resilient to noise and therefore present high coherence times, at least in the case of spin qubits and magnetic noise: as the at first order…
agaitaarino
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4
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3 answers

Why does joint ground state not change under action of beam splitting unitary operator?

How can one show that $\hat{U}|00\rangle=|00\rangle$ where $\hat{U}=e^{-igt(\hat{a}^\dagger_2\hat{a}_1+\hat{a}^\dagger_1\hat{a}_2)}$ and $|00\rangle$ is the unique joint zero eigenstate of the annihilation operators $\hat{a}_1$ and $\hat{a}_2$, i.e.…
heromano
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4
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2 answers

Fermionic occupation operator and nearest neighbor Fermionic hopping interaction as a qubit operator

How to express Fermionic occupation operator $(\hat{a}_j^\dagger\hat{a}_j)$ and nearest neighbor Fermionic hopping interaction ($H_h= J\sum_{i=1}\hat{a}_i^\dagger \hat{a}_{i+1}+\hat{a}_{i+1}^\dagger \hat{a}_{i})$ as a qubit operators.
heromano
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