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Jaynes–Cummings–Hubbard model

Jaynes–Cummings–Hubbard model is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Jaynes–Cummings–Hubbard model rather than just read about it. In short: The Jaynes–Cummings–Hubbard (JCH) model is a many-body quantum system modeling the quantum phase transition of light. As the name suggests, the Jaynes–Cummings–Hubbard model is a variant on the Jaynes–Cummings model; a one-dimensional JCH model consists of a chain of N coupled single-mode cavities, each with a two-level atom.

Jaynes–Cummings–Hubbard model — main illustration
Jaynes–Cummings–Hubbard model — illustration

Key takeaways

  • Jaynes–Cummings–Hubbard model belongs to physics; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Jaynes–Cummings–Hubbard model to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Jaynes–Cummings–Hubbard model from memory before moving on to harder problems.

Reference excerpt

The Jaynes–Cummings–Hubbard (JCH) model is a many-body quantum system modeling the quantum phase transition of light. As the name suggests, the Jaynes–Cummings–Hubbard model is a variant on the Jaynes–Cummings model; a one-dimensional JCH model consists of a chain of N coupled single-mode cavities, each with a two-level atom. Unlike in the competing Bose–Hubbard model, Jaynes–Cummings–Hubbard dynamics depend on photonic and atomic degrees of freedom and hence require strong-coupling theory for treatment. One method for realizing an experimental model of the system uses circularly-linked superconducting qubits.

History The combination of Hubbard-type models with Jaynes-Cummings (atom-photon) interactions near the photon blockade regime originally appeared in three, roughly simultaneous papers in 2006. All three papers explored systems of interacting atom-cavity systems, and shared much of the essential underlying physics. Nevertheless, the term Jaynes–Cummings–Hubbard was not coined until 2008.

Properties Using mean-field theory to predict the phase diagram of the JCH model, the JCH model should exhibit Mott insulator and superfluid phases.

Hamiltonian The Hamiltonian of the JCH model is ( ℏ = 1 {\displaystyle \hbar =1} ):

H = ∑ n = 1 N ω c a n † a n + ∑ n = 1 N ω a σ n + σ n − + κ ∑ n = 1 N ( a n + 1 † a n + a n † a n + 1 ) + η ∑ n = 1 N ( a n σ n + + a n † σ n − ) {\displaystyle H=\sum _{n=1}^{N}\omega _{c}a_{n}^{\dagger }a_{n}+\sum _{n=1}^{N}\omega _{a}\sigma _{n}^{+}\sigma _{n}^{-}+\kappa \sum _{n=1}^{N}\left(a_{n+1}^{\dagger }a_{n}+a_{n}^{\dagger }a_{n+1}\right)+\eta \sum _{n=1}^{N}\left(a_{n}\sigma _{n}^{+}+a_{n}^{\dagger }\sigma _{n}^{-}\right)}

… excerpt ends here. Continue reading the full article.

Illustrations

Jaynes–Cummings–Hubbard model: Tunnelling of photons between coupled cavities. The 
  
    
      
        κ
      
    
    {\displaystyle \kappa }
  
 is the tunnelling rate of photons.
Tunnelling of photons between coupled cavities. The κ {\displaystyle \kappa } is the tunnelling rate of photons.
Jaynes–Cummings–Hubbard model: Illustration of the Jaynes–Cummings model. In the circle, photon emission and absorption are shown.
Illustration of the Jaynes–Cummings model. In the circle, photon emission and absorption are shown.

Worked examples

Example 1 — a first encounter with Jaynes–Cummings–Hubbard model

Start with the simplest possible case. Write down what Jaynes–Cummings–Hubbard model claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Jaynes–Cummings–Hubbard model before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Jaynes–Cummings–Hubbard model ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Jaynes–Cummings–Hubbard model

In research
Jaynes–Cummings–Hubbard model appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Jaynes–Cummings–Hubbard model in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Jaynes–Cummings–Hubbard model is common in secondary-school and first-year university syllabi. It links to neighbouring topics Quantum optics, so understanding it makes those chapters shorter.
In everyday life
Look for Jaynes–Cummings–Hubbard model outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Jaynes–Cummings–Hubbard model in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Jaynes–Cummings–Hubbard model means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Jaynes–Cummings–Hubbard model out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Jaynes–Cummings–Hubbard model in simple terms?

The Jaynes–Cummings–Hubbard (JCH) model is a many-body quantum system modeling the quantum phase transition of light. As the name suggests, the Jaynes–Cummings–Hubbard model is a variant on the Jaynes–Cummings model; a one-dimensional JCH model consists of a chain of N coupled single-mode cavities…

Why does Jaynes–Cummings–Hubbard model matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Jaynes–Cummings–Hubbard model?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Jaynes–Cummings–Hubbard model.

Tags

  • Quantum optics

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