Question

This property names a type of statement exemplified by one involving the log squared of the Mandelstam variable s, named for Marcel Froissart (“fwah-SAR”). The Wightman axioms entail the existence of a representation of the Poincaré (“pwann-ka-RAY”) group with this property in a QFT’s Hilbert space. (10[1])Operators with this property cannot copy arbitrary (10[1])quantum states according (10[1])to the no-cloning (10[1])theorem. (10[2])One of a type of bound named for this property can be derived from the fact that the S-matrix (10[1])displays it. This property is held by all matrices representing quantum gates (10[2])and by the (-5[1])time (10[1])evolution operator. (10[2]-5[1])The gauge group of QED is the group of matrices (10[2])with (10[1])this property (10[1])of dimension (10[1])1. When multiplied by two vectors, (10[1])matrices with this property leave the Hermitian (“her-MISH-un”) inner product unaltered. (10[1])For 10 points, name this property of a matrix whose conjugate transpose is its inverse. (0[1])■END■ (10[1]0[2])

ANSWER: unitarity [or unitary or unitary matrix or unitary matrices or unitary operators or unitarity operators; accept unitary bound or unitarity bound; accept unitary group; accept unitary representations; prompt on U or U(1)]
<Physics>
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Summary

2024 ACF Nationals2024-04-21Y2291%0%9%87.90

Buzzes

PlayerTeamOpponentBuzz PositionValue
Tim MorrisonStanfordPurdue4310
Adam FineChicago AArizona State5010
Mattias EhatammWaterlooBerkeley A5310
Vincent DuNorth Carolina AFlorida5610
Simon GorbatyDukeJohns Hopkins5710
Rasheeq AzadNorth Carolina BToronto B5710
Shiv SeshanChicago DColumbia B7610
Karthik PrasadCornell BGeorgia Tech8810
Sky LiToronto AVirginia8810
Alex AkridgeIndianaIowa State91-5
Mason YuBrownOttawa9210
Asha BasuMcGillMinnesota A9410
Cory SmithKentuckyBerkeley B9410
Andrew SalijNorthwesternYale B94-5
Jeremy CummingsWUSTL BTexas10410
Matthew LehmannWUSTL AMinnesota B10410
Danny HanPennVanderbilt10510
Andrew WangIllinoisChicago C10710
Fred GarveyTruman StateMaryland10910
Matthew SiffYale ASouth Carolina11510
Connor BlakeChicago BHarvard12510
Conor ThompsonIowa StateIndiana1400
Mark TawfikRutgersNYU1410
Lydia TarekegnYale BNorthwestern1410
Eshan PantNYURutgers14110