Questions tagged [photonics]
It is the branch of physics and engineering concerned with the properties and transmission of photons. Use this tag for those questions about photonics which are relevant to quantum computing.
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Hong Ou Mandel interference and bell basis measurment
It is well known that using Hong Ou Mandel interference in polarization one can only detect 2 out of the 4 bell states($|\psi^+\rangle$ and $|\psi^-\rangle$ can be detected but $|\phi^+\rangle$ and $|\...
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How to physically implement a CNOT gate with a photon and a cold atom?
If I have qubits in the same platform (superconducting, photon or cold atoms), the implementation of CNOT gates is relatively well-known. However, if I have a photon and a cold atom, how am I supposed ...
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In a QKD protocol such as BB84 how do Alice and Bob deal with lost or undetected photons?
In a quantum key distribution protocol such as BB84 how do Alice and Bob deal with lost or undetected photons in practice?
Imagine Alice sends 1001 using X Z X Z bases. Bob then receives 101 (second ...
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Is the choice of Measurement-based model specific to the hardware technology?
Most photonic hardware providers seem to prefer Measurement-based quantum computing (MBQC) over the gate-based model.
Is this due to some limitations of the corresponding hardware technologie?
If yes,...
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How do photon gates act on ground and excited states?
https://strawberryfields.ai/photonics/conventions/gates.html#displacement
The above is the only profile of Photon Gate from Strawberry Fields.
I have the following doubts about Photon Gate:
Which of ...
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What do the angles in a Poincaré sphere represent?
I understand the principle of the Bloch sphere. You write your state in the following way:
$$|\Psi\rangle = \cos(\theta/2)|0\rangle+e^{i\varphi}\sin(\theta/2)|1\rangle.$$
The angles $\varphi,\theta$ ...
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Where is my mistake in using a measurement operator instead of Born’s rule to calculate the probability of detecting photons at an arbitrary angle?
As I asked in this question: How can I calculate the measuring probabilities of a two qubit state along a certain axis?
From here I know how to calculate the probability of measuring a general state ...
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Two-photon N00N state through Mach-Zehnder interferometer
I am interested in modelling a two-photon N00N state sent through a Mach-Zehnder interferometer, which consists of a beam-splitter (50:50), a phase shift operator on the first mode, a phase shift ...
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What is the best way to model a polarizer?
If I have a photon reaching a polarizer, I can think of a polarizer as an operator of $P=a^\dagger_Va_V$ where $a^\dagger_V$ creates a photon with vertical polarization (V).
However, on the other ...
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Type I fusion Gate
In the type I fusion gate of the Rudolph-Browne protocol,
I fail to understand how the detection of a photon means the entanglement of the two Bell pairs.
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What is complete structures of the photonic quantum computers?
I am interested in studying quantum computers based on photonic integrated circuits. I am looking for a site, article, book, or material that will introduce the process of its implementation step by ...
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What is the optimal hardware for quantum computing, and what factors contribute to its preference?
In conventional computing, the use of CMOS (Complementary Metal Oxide Semiconductor) technology as the foundational circuitry for digital logic gates in CPUs has become the industry norm. CMOS's ...
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What's the difference between Superconductor, Photonics, and Nuclear Magnetic Resonance implementation of the physical QC?
I'm a bit new to Quantum Computing and I wonder why organisations are using different physical architecture.
I realise that any physical implementation can be valid as long as it uses the fundamentals ...
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How to entangle 2 qubits using a polarizing beam splitter?
A polarizing beam splitter splits a continuous beam of photons in 2 directions:
(from here)
(from here)
I am curious and have a few related questions about using simple optics in quantum computing:
...
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Two-way quantum computers (like in Ising model) - are they possible? Could solve general NP problems? [closed]
Standard one-way quantum computers (1WQC) allow for e.g. Shor, Grover algorithms, however, general NP problems seem too difficult for them(?) - bringing an open question if they could be somehow ...
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