Entangling four logical qubits beyond break-even in a nonlocal code
- URL: http://arxiv.org/abs/2406.02666v1
- Date: Tue, 4 Jun 2024 18:00:00 GMT
- Title: Entangling four logical qubits beyond break-even in a nonlocal code
- Authors: Yifan Hong, Elijah Durso-Sabina, David Hayes, Andrew Lucas,
- Abstract summary: Quantum error correction protects logical quantum information against environmental decoherence.
We encode the GHZ state in four logical qubits with fidelity $ 99.5 pm 0.15 % le F le 99.7 pm 0.1% $ (after postselecting on over 98% of outcomes)
Our results are a first step towards realizing fault-tolerant quantum computation with logical qubits encoded in geometrically nonlocal quantum low-density parity check codes.
- Score: 0.0
- License: http://creativecommons.org/licenses/by/4.0/
- Abstract: Quantum error correction protects logical quantum information against environmental decoherence by encoding logical qubits into entangled states of physical qubits. One of the most important near-term challenges in building a scalable quantum computer is to reach the break-even point, where logical quantum circuits on error-corrected qubits achieve higher fidelity than equivalent circuits on uncorrected physical qubits. Using Quantinuum's H2 trapped-ion quantum processor, we encode the GHZ state in four logical qubits with fidelity $ 99.5 \pm 0.15 \% \le F \le 99.7 \pm 0.1\% $ (after postselecting on over 98% of outcomes). Using the same quantum processor, we can prepare an uncorrected GHZ state on four physical qubits with fidelity $97.8 \pm 0.2 \% \le F\le 98.7\pm 0.2\%$. The logical qubits are encoded in a $[\![ 25,4,3 ]\!]$ Tanner-transformed long-range-enhanced surface code. Logical entangling gates are implemented using simple swap operations. Our results are a first step towards realizing fault-tolerant quantum computation with logical qubits encoded in geometrically nonlocal quantum low-density parity check codes.
Related papers
- Supervised binary classification of small-scale digits images with a trapped-ion quantum processor [56.089799129458875]
We show that a quantum processor can correctly solve the basic classification task considered.
With the increase of the capabilities quantum processors, they can become a useful tool for machine learning.
arXiv Detail & Related papers (2024-06-17T18:20:51Z) - Creating entangled logical qubits in the heavy-hex lattice with topological codes [0.0]
In this work we show how this bug can be turned into a feature.
We demonstrate entanglement between logical qubits with code distance up to $d = 4$.
We verify the violation of Bell's inequality for both the $d=2$ case with post selection featuring a fidelity of $94%$.
arXiv Detail & Related papers (2024-04-24T17:02:35Z) - Towards large-scale quantum optimization solvers with few qubits [59.63282173947468]
We introduce a variational quantum solver for optimizations over $m=mathcalO(nk)$ binary variables using only $n$ qubits, with tunable $k>1$.
We analytically prove that the specific qubit-efficient encoding brings in a super-polynomial mitigation of barren plateaus as a built-in feature.
arXiv Detail & Related papers (2024-01-17T18:59:38Z) - Logical quantum processor based on reconfigurable atom arrays [27.489364850707926]
We report the realization of a programmable quantum processor based on encoded logical qubits operating with up to 280 physical qubits.
Results herald the advent of early error-corrected quantum computation.
arXiv Detail & Related papers (2023-12-07T01:54:45Z) - High-threshold and low-overhead fault-tolerant quantum memory [4.91491092996493]
We present an end-to-end quantum error correction protocol based on a family of LDPC codes with a high encoding rate.
We show that 12 logical qubits can be preserved for nearly one million syndrome cycles using 288 physical qubits.
arXiv Detail & Related papers (2023-08-15T17:55:12Z) - Protecting Expressive Circuits with a Quantum Error Detection Code [0.0]
Quantum error correction opens the way for quantum computers to speed up relevant tasks like simulating quantum systems.
We develop the $[k+2k,]]2$ quantum error detection code, for implementations on existing trapped-ion computers.
A high-fidelity -- though non fault-tolerant -- compilation of this universal gate set is possible thanks to the two-qubit physical rotations.
arXiv Detail & Related papers (2022-11-12T16:46:35Z) - Suppressing quantum errors by scaling a surface code logical qubit [147.2624260358795]
We report the measurement of logical qubit performance scaling across multiple code sizes.
Our system of superconducting qubits has sufficient performance to overcome the additional errors from increasing qubit number.
Results mark the first experimental demonstration where quantum error correction begins to improve performance with increasing qubit number.
arXiv Detail & Related papers (2022-07-13T18:00:02Z) - Towards Demonstrating Fault Tolerance in Small Circuits Using Bacon-Shor
Codes [5.352699766206807]
We study a next step - fault-tolerantly implementing quantum circuits.
We compute pseudo-thresholds for the Pauli error rate $p$ in a depolarizing noise model.
We see that multiple rounds of stabilizer measurements give an improvement over performing a single round at the end.
arXiv Detail & Related papers (2021-08-04T14:24:14Z) - Exponential suppression of bit or phase flip errors with repetitive
error correction [56.362599585843085]
State-of-the-art quantum platforms typically have physical error rates near $10-3$.
Quantum error correction (QEC) promises to bridge this divide by distributing quantum logical information across many physical qubits.
We implement 1D repetition codes embedded in a 2D grid of superconducting qubits which demonstrate exponential suppression of bit or phase-flip errors.
arXiv Detail & Related papers (2021-02-11T17:11:20Z) - Fault-tolerant Coding for Quantum Communication [71.206200318454]
encode and decode circuits to reliably send messages over many uses of a noisy channel.
For every quantum channel $T$ and every $eps>0$ there exists a threshold $p(epsilon,T)$ for the gate error probability below which rates larger than $C-epsilon$ are fault-tolerantly achievable.
Our results are relevant in communication over large distances, and also on-chip, where distant parts of a quantum computer might need to communicate under higher levels of noise.
arXiv Detail & Related papers (2020-09-15T15:10:50Z) - Entangling logical qubits with lattice surgery [47.037230560588604]
We show the experimental realization of lattice surgery between two topologically encoded qubits in a 10-qubit ion trap quantum information processor.
In particular, we demonstrate entanglement between two logical qubits and we implement logical state teleportation.
arXiv Detail & Related papers (2020-06-04T18:00:09Z)
This list is automatically generated from the titles and abstracts of the papers in this site.
This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.