As any biologist will happily tell you, at some point even a physicist must find a suitable mate. Otherwise, where do baby physicists come from? Therefore, it follows that at some point in any physicist's life, there will be a need to procreate. Please see the earlier physicists guide to identifying the sexes, as attempting to procreate with same gender people will prove fruitless. And sometimes painful.
Whilst it may have been perfectly acceptable to perform solitary procreation for much of a physicist's life, this is unlikely to lead to any kind of offspring. Physicists, especially those of the theoretical bent, will know that unlikely is not the same as impossible, and this is why there are less theoretical physicists.
In order to reach the end goal of progeny, physicists will need to go through a stage known as dating. There are several elements to dating, the most important aspect of which is 'romance'. Romance comes from the Latin word 'Roman', which means 'a man from Rome' and not 'somebody with roaming hands'. Men from Rome invented romance, which is why the word is an amalgamation of 'Rome' and 'Man'.
Romance, unlike refraction, is not an exact science with several hidden variables. It is more akin to quantum states. Several experiments will be required to uncover the precise values for these hidden variables, with the added Heisenberg uncertainty that causes the values required in each experiment being altered prior to the start of the experiment.
For example, cut flowers (flowers that have been removed from the plant that grew them) are very romantic in most circumstances, and can ultimately lead to procreation. This is not the case for all flowers or all romantic liaisons. Lilies, for example, have connotations above and beyond long stamens and white flowers. Romantic interests consider the lily a symbol of death, despite the fact that all cut flowers are, in effect, dying from the moment that they are cut. Furthermore, like all physicists, some romantic targets are allergic to flowers. Providing a 'date' with antihistamines along with the flowers 'just to be on the safe side', is 'bad romance'.
That said, the gift of flowers, even of the wrong type, or to an allergen susceptible individual is rarely a bad move.
Chocolate is more problematic. Whilst there isn't a date on the planet that would not eat their own weight in chocolate, the gift of chocolate can result in awkward questions such as 'are you trying to make me fat?'. Pointing out that the person is already fat is also 'bad romance'.
This leads onto the subject of words. When attempting 'good romance' it is worth saying as little as possible. Leave the subject of occupations until a romantic target can look past the fact you are a physicist. Attempting to show erudite knowledge of the inner working of a hydrogen bond is likely to be the only bond mentioned all night. Similarly, explaining how a window works strangely leaves many people cold and unresponsive to romantic overtures.
Keep words simple, and subject matters as nonreactive as a sterile neutrino. The discussion of Brian Cox, Albert Einstein or Fozzie Bear is acceptable, but do not discuss more obscure heroes. As physicists are restricted to conversations about physics, read up on the physics of the culinary arts. An in depth knowledge in creme brule is quite often regarded as 'good romance' even when the exact thermal equations needed for a crisp topping are a major topic of discussion.
Other subjects classified as 'bad romance' are:
1. Your date's lack of hair.
2. The reason why red is an unsuitable colour choice for clothing.
3. How short-sightedness could be cured by the application of pressure to the eye (with demonstration)
4. The origin of the word 'film'.
5. Putting discussion topics in numbered lists.
In order to ensure a smooth romance, it is wise for physicists to avoid almost all of their usual topics of conversation. For this reason extensive research has shown that the gift of flowers followed by a trip to the cinema is 'good romance'. This prevents uncomfortable silences, as silence it is expected. Thus do not discuss the merits of the variety of projector mechanisms. As to the choice of film, it is 'bad romance' to choose anything with the word 'horror' in the title, and 'good romance' to choose anything with RomCom in the title, despite the latter not being a real word.
Armed with this knowledge any physicist should be able to be successful in replicating their parents experiments in procreation. And as any good physicist knows, accurate replication is the Holy Grail.