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Travelling Ballot Based Protocol: Difference between revisions
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==Protocol Description== | ==Protocol Description== | ||
*Setup phase: | |||
T prepares the state <math>|\phi_0\rangle =\dfrac{1}{\sqrt{N}}\sum_{j=0}^{N-1}|j\rangle_V |j\rangle_T</math>, keeps the second qudit and passes the first to voter <math> V_1</math> as the ballot qudit. | |||
* Casting phase: | |||
For k = 1, ... ,N, <math>V_k </math>receives the ballot qudit and applies the unitary <math>U^{v_{k}}=\sum_{j=0}^{N-1}|j+1\rangle \langle j|</math>, where <math>v_k = 1</math> signifies a yes vote and <math>v_k = 0</math> a no vote. | |||
Then, <math> V_k</math> forwards the ballot qudit to the next voter <math>V_{k+1}</math> and <math> V_N</math> to T. | |||
* Tallying phase: | |||
The global state held by T after all voters have voted is: | |||
<math>|\phi_N\rangle =\dfrac{1}{\sqrt{N}}\sum_{j=0}^{N-1}|j+m\rangle_V|j\rangle_T</math> | |||
T measures the two qudits in the computational basis, subtracts the two results, and obtains the outcome m. | |||
==Further Information== | ==Further Information== | ||
<div style='text-align: right;'>''*contributed by Sara Sarfaraz''</div> | <div style='text-align: right;'>''*contributed by Sara Sarfaraz''</div> | ||