Steady-state entanglement generation for non-degenerate qubits

summary

The gist

The gist We propose a scheme to dissipatively produce steady-state entanglement in a two-qubit system, via an interaction with a bosonic mode.

In short

The paper proposes a method to create steady-state entanglement between two qubits by interacting them with a bosonic mode and compensating for dissipation with an external pump field. It shows that this process can be understood through analogies to EIT and STIRAP. The scheme allows for the preparation of maximally entangled states, including an adiabatic transfer mechanism.

Key concepts

System Hamiltonian: This mathematical description defines the total energy and interactions within the two-qubit system coupled to a bosonic mode. It includes terms for qubit energies, coupling strengths ($g$), and the interaction with the bosonic field ($ar{a}ar{a}$), setting up the physics of how energy flows between components.
Dark Eigenstate: In this context, a dark eigenstate is a specific quantum state that does not contain an excited component (like $| ext{ extPsi+i} angle$). This state is crucial because it represents the desired entangled target state when certain conditions, like the EIT condition ($g riangle$), are met.
EIT and STIRAP Analogy: The dynamics of generating entanglement are compared to Electromagnetically Induced Transparency (EIT) and Stimulated Raman Adiabatic Passage (STIRAP). EIT describes how the system stays in a specific dark state, while STIRAP describes an adiabatic process that smoothly transfers the population into that target entangled state.
Concurrence: Concurrence is a measure used to quantify the degree of entanglement present between two quantum systems. The paper uses this metric to track how strong the entanglement is as parameters like detuning ($ riangle$) and coupling ($g$) are varied, helping to identify optimal conditions for generating high entanglement.

Terminology used across episodes

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Retrieval-Augmented Generation (RAG) — explained in 16 episodes
Interpretability — explained in 15 episodes
Quantum Fisher Information (QFI) — explained in 15 episodes

This episode discusses

The paper

Steady-state entanglement generation for non-degenerate qubits · Read on arXiv

Murilo H. Oliveira, * Gerard Higgins, † Chi Zhang, ↓ Ana PredojeƖvǧ, Markus Hennrich, Romain Bachelard, 3 and Celso J Villas-Boas

Departamento de Física, Universidade Federal de São Carlos · Department of Physics, Stockholm University · ↔Université C⃴te d’Azur, CNRS, Institut de Physique de Nice

DOI: 10.1103/PhysRevA.107.023706

Transcript

Introduction to the show: ident: Quantum Radio. Generated commentary on the latest quantum physics and condensed matter papers.

Kai: Today's paper: "Steady-state entanglement generation for non-degenerate qubits".

Mira: The gist We propose a scheme to dissipatively produce steady-state entanglement in a two-qubit system, via an interaction with a bosonic mode.

Kai: First, who's behind it and why it matters.

Paper summary: Kai: So to recap this paper about "Steady-state entanglement generation for non-degenerate qubits," they propose a scheme to make steady-state entanglement in two qubits through interaction with a bosonic mode.

Mira: They claim the system gets driven into a stationary entangled state, and they counter the mode dissipation by injecting energy via a coherent pump field.

Lev: And they also show how you can adiabatically transfer all of that population into the specific entangled state they want to achieve.

Kai: The paper explains that these dynamics are analogous to electromagnetically induced transparency for the steady-state production and stimulated Raman adiabatic passage for the transfer part.

Mira: What's important is their system model where the bosonic mode is symmetrically detuned from each qubit, specifically omega e(one) = omega m - and omega e(two) = omega m + <ref:2205.10590#pg1>.

Lev: They also describe a specific Hamiltonian, equation (one), which sets up the coupling between the qubits and the bosonic mode <ref:2205.10590#pg1>.

Kai: And they identify this dark eigenstate, D, which in certain conditions transforms into their maximally entangled target state,-i >

Conclusion: Kai: So looking at "Steady-state entanglement generation for non-degenerate qubits," the authors are Murilo H. Oliveira, Gerard Higgins, Chi Zhang, Ana Predojević, Markus Hennrich, Romain Bachelard and Celso J. Villas-Boas.

Mira: The implications seem to be showing a practical way to generate steady-state entanglement in systems where the qubit frequencies aren't exactly the same as the cavity frequency.

Lev: It’s about using that bosonic mode interaction and clever pumping to keep the system entangled even when it naturally wants to decay into a zero energy ground state.

Kai: And they show that by setting up certain conditions, like g being fulfilled, you can drive the system toward that maximally entangled target state-i >.

Mira: It’s about using these analogies with EIT and STIRAP to understand how this steady-state entanglement is actually built in the dynamics.

Lev: From a hardware side, it suggests that if we can control those couplings and detunings, we might be able to engineer robust entangled states in superconducting qubit setups.

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