Remote Gottesman-Kitaev-Preskill Entanglement Generation between Trapped Ions

summary

Video file (mp4)

The gist

The gist The protocol proposes a heralded method for generating remote entanglement between Gottesman–Kitaev–Preskill qubits encoded in trapped ion motional modes by using internal electronic

In short

The protocol generates remote entanglement between Gottesman-Kitaev-Preskill (GKP) qubits encoded in trapped ion motional modes using internal electronic states to interface them with emitted photons. The method involves preparing local GKP states, converting motional entanglement into a motion-ion-photon state, and using Bell measurements to distill the final logical Bell pair. Realistic noise models show that fidelity remains above 95% under certain conditions.

Key concepts

Gottesman--Kitaev--Preskill (GKP) qubits
These are error-corrected logical qubits that encode information in the continuous variable (CV) degree of freedom, specifically the motional modes of trapped ions. They are robust against certain types of errors, making them suitable for scalable quantum networks.
Heralded Protocol
This is a method where entanglement generation is confirmed by detecting an ancillary signal, such as emitted photons. In this protocol, successful photon detection heralds the creation of the desired remote entanglement between the two distant GKP qubits.
Motional Encoding
Information in this scheme is stored not in internal electronic states but in the quantized motion (vibrational modes) of trapped ions. This motional degree of freedom is then coupled to photonic qubits via the ion's internal electronic states, allowing for remote distribution.

Terminology used across episodes

This episode discusses

The paper

Remote Gottesman-Kitaev-Preskill Entanglement Generation between Trapped Ions · Read on arXiv

Haruki Aoki, *, Kazufumi Tanji, Shohei Kiryu, Masahiro Takeoka, †Junko Ishi-Hayase

School of Mathematical and Physical Sciences, Keio University · Department of Electronics and Electrical Engineering, Keio University Department of Electronics and Electrical Engineering, National Institute of Information and Communications Technology

Distributing entanglement directly between error-corrected logical qubits is an important capability for scalable quantum networks. We propose a heralded protocol for generating remote entanglement between Gottesman--Kitaev--Preskill qubits encoded in the motional modes of spatially separated trapped ions, using the internal electronic states to interface the motional qubits with emitted photons. We derive the protocol for single-rail and polarization photonic encodings and evaluate the effects of finite GKP squeezing, photon loss, photon recoil, motional heating, and motional dephasing on the decoded logical state. Moreover, we numerically analysed the fidelity of distributed logical Bell-pair fidelity. We find that one can achieve more than 95% of fidelity in the realistic situation. The protocol combines motional-control and photonic-networking operations that have already been demonstrated in trapped-ion experiments.

Transcript

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

Kai: I'm Kai.

Mira: And I'm Mira, here with Lev.

Kai: Today's paper: "Remote Gottesman-Kitaev-Preskill Entanglement Generation between Trapped Ions".

Mira: The gist The protocol proposes a heralded method for generating remote entanglement between Gottesman–Kitaev–Preskill qubits encoded in trapped ion motional modes by using internal electronic states to interface these motional…

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

Paper summary: Kai: So, to wrap up this paper "Remote Gottesman-Kitaev-Preskill Entanglement Generation between Trapped Ions", the main thing is that they successfully generated remote entanglement between GKP qubits encoded in trapped ion motional modes by interfacing them with emitted optical photons using internal electronic states.

Mira: The protocol derives this for single-rail and polarization photonic encodings, and they evaluated all these physical imperfections like photon loss, recoil, heating, and dephasing on the decoded logical state.

Lev: The results show that you can achieve more than ninety-five percent of fidelity in the realistic situation when considering those noise parameters <ref:2610.21754#pg3>.

Kai: It’s a solid result because it combines motional control and photonic-networking operations that have already been demonstrated experimentally in trapped-ion experiments <ref:2610.21754#pg2>.

Mira: The implications are that this gives us a way to distribute entanglement directly between error-corrected logical qubits, which is an important capability for scalable quantum networks <ref:2610.21754#pg1>.

Lev: It provides a link-level characterization of the proposed remote motional-GKP entanglement protocol over experimental noise parameters, which is what we need to know when we try to build this on real hardware <ref:2610.21754#pg3>.

Conclusion: Kai: So, we've looked at how these trapped ion motional qubits can be linked up using photons mediated by their internal electronic states, and now we're getting to the finish line on this paper, "Remote Gottesman-Kitaev-Preskill Entanglement Generation between Trapped Ions."

Mira: Yeah, so the main thing here is they developed a heralded protocol for making remote entanglement between those GKP logical qubits encoded in the ion motion.

Lev: What that means is you can build these error-corrected logical links across space without having to physically bring the ions together to do it directly.

Kai: Right, and what's interesting about this paper is they didn't just show a theoretical setup; they really stress-tested it against all the messy physical stuff.

Mira: They evaluated photon loss, which is a real problem in any optical network, and also things like recoil during that photon emission process.

Lev: And they modeled motional heating and dephasing—things that actually mess up the quantum state of the ion motion—and found that even with those errors present, you can still get above ninety-five percent fidelity on the logical Bell state.

Kai: So, what does this actually change for us if we're building these bigger quantum networks?

Mira: It means we're looking at a way to distribute entanglement directly between error-corrected qubits, which is a huge step toward making those networks scalable.

Lev: The real takeaway is that they combined motional control and photonic networking operations that we already have working in trapped-ion experiments, so this isn't some totally new physics thing; it’s an engineering challenge solved with existing tools.

Kai: So, yeah, the title itself points to something practical—getting entanglement between GKP states remotely.

Mira: And the authors are clearly focused on making sure the protocol works in a realistic setting where noise is actually present.

Lev: They gave us a clear link-level characterization of this whole protocol over those noise parameters we talked about earlier.

Kai: That’s what we need to see when moving from simulation to actual hardware performance metrics, so it sets a baseline for what's achievable on real systems.

More episodes

← Home