Red Boundary Packet Cross-Scan - Ion-Trap Qubits: Sidebands, Shared Modes, and Fluorescence Readout Step by Step

A red sideband rejects only when the start packet has no lower neighbor. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

At packet zero, red energy matches but the move is rejected

The drive energy is still six joules, but packet zero has no lower packet, so the accepted bit is 0.

n=0,\quad E_{\text{drive}}=6\ \text{J},\quad a=0

At packet one, red sideband can step to zero

The same six-joule drive now has a valid target packet, so the accepted bit becomes 1.

n:1\to0,\quad a=1

At packet two, red sideband steps down to one

The packet index changes from 2 to 1 with the same accepted bit.

n:2\to1,\quad a=1

The boundary is about packet availability, not drive energy

All three rows show the same six-joule red drive. Only the starting packet decides whether the target packet is legal.

\begin{array}{c|c|c|c}n_{\text{start}}&E_{\text{drive}}&n_{\text{end}}&a\\0&6\ \text{J}&0&0\\1&6\ \text{J}&0&1\\2&6\ \text{J}&1&1\\\end{array}