Alex Jensen

Alex Jensen is a Caltech Physics doctoral student and Sheldon Cooper's assistant. A native of Des Moines, Iowa, she graduated summa cum laude with a concentration in theoretical physics from Stanford University. Inspired by her father, a SETI astronomer, her dissertation concerns looking for Trojan asteroids at Earth's L5 Lagrange point. She gave up an opportunity at to come work for Sheldon.

She is introduced in S06E03 "The Higgs Boson Observation", when Sheldon hires her. Alex happens to be quite skilled with flattery, shown when she uses it to persuade Sheldon to hire her, even though immediately beforehand he insists that flattery does not work on him. When Leonard and Raj stop in to visit Sheldon, they meet Alex, whom Raj immediately falls for. Later, Alex meets Penny, who she mistakes for Leonard's assistant.

Alex is next seen in S06E08 "The 43 Peculiarity", where she shows an obvious interest in Leonard, though Leonard remains oblivious to her flirting and signals of attraction to him. This is further explored in S06E12 "The Egg Salad Equivalency", when Alex suggests that they could discuss the physics lecture she was attending over dinner. Although Leonard remains faithful to Penny, her offer does not stop his ego from inflating for the rest of the episode. Sheldon, however, is jealous that she is showing any form of interest in any physicist besides himself, and attempts to discourage her advances and keep her focused on his needs. His efforts backfire spectacularly when she takes offense to his numerous condescending and demeaning remarks about her biological urges, causing her to file a sexual harassment complaint with a Human Resources administrator. The HRA's attempts to show Sheldon that his actions were offensive seem initially successful, with Sheldon later revealing to Alex that he is required to complete an online sexual harassment seminar – however, as he unaffectedly deems his time far too valuable, he asks Alex to take it in his place.

Alex Jensen next appears in S06E16 "The Tangible Affection Proof". With Valentine's Day approaching, Sheldon gets Alex to help him find a Valentine's Day gift for Amy. Sheldon gives Alex two thousand dollars in various crumpled bills that he finds in his pockets and his desk, and instructs Alex on Amy's interests (monkeys and the color grey) so that Alex can find an appropriate gift for Amy.