Questions tagged [qldpc]
9 questions
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Preserving distance during stabilizer measurements by alternating interaction order from round to round?
On the rotated surface code, it is known that choosing a "bad" interaction order when measuring stabilizers leads to a halving of the effective code distance. This is because of hook errors: a single error on the measurement qubit can propagate to…
Exorus Koh
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4
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1 answer
Distance of the Lifted Product codes
The hypergraph product code has distance determined by $\min\{d_1,d_2\}$, where $d_1,d_2$ are distances of the classical codes respectively (assuming PCM full rank). What about lifted product codes? I'm wondering if such relation also exists, e.g.…
AndyLiuin
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3
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Questions about the construction of quantum tanner code
I am confused about some definitions of quantum tanner code when self-learning the lecture notes lecture 19 and lecture20. Following the definitions in the link, we have a group $G$, two generating set $A$ and $B$ with the same size $\Delta$, two…
qmww987
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Why are there no practical applications of classical expander codes?
In recent years, there is a surging amount of works on qLDPC codes achieving linear/almost linear distance. A lot of them are based on fancy products of expander codes. However, it seems like this is yet far from practical. My question is, classical…
AndyLiuin
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2
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How to write a function that can automatically transform the Parity check matrix of any code into a detector error model
I'm new to Stim, so please bear with me if I ask some questions that might seem silly in the end.
Lately, I've been eager to simulate the errorcorrection effects of the BB code, HGP code, and other quantum low density parity check (qLDPC) codes…
Zach
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2
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1 answer
BP decoders for qLDPC codes
Do BP (BP-OSD, BP-LSD) decoders process 3-dimensional graphs of a simple noise model, where the third dimension is the time dimension, like how the MWPM decoder works for surface codes? Is there a specific procedure for attacking measurement errors,…
user1232537
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Compiling logical operators from joint measurements
Lattice surgery on surface codes, and recent generalisations to QLDPC codes, perform computation via sequences of joint logical measurements.
A lot of work has gone into reducing the space-time overhead of such logical measurements, and results are…
user289
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Threshold Calculation for Good Quantum LDPC Codes
The threshold for different types of surface codes has been studied under various noise models (see this paper / arXiv and other references obtained by a quick literature search).
I am curious about the status of similar calculations for good…
zeroknowledgeprover
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Simulating BB codes in STIM
Page 3 of the supplementary information of High-threshold and low-overhead fault-tolerant quantum memory (Nature, 2024) gives an algorithm for the syndrome measurements of arbitrary BB codes. I'm curious about how to turn this into a STIM…
ebit157
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