Do you engage with him in banter or do you discuss the weather? Do you talk or do you listen? Do you invite him to stay the night or ask him to leave? Do you take care of her or betray her? Do you ask her to spend the rest of her life with you or not? Do you take that last chance to connect or do you let him go? Do you brave an illness or do you choose death?
And is there another you in another universe of the multiverse landscape confronted with the same questions but making different choices? Are there an infinite number of universes containing an infinite number of copies of you living out different variations of your life? This is the premise of Nick Payne’s stimulating play, Constellations, performing this week at the Asper Centre for Theatre and Film by Theatre by the River featuring Mel Marginet and Derek Leenhouts. Together with Vesna Milosevic-Zdjelar and Andrew Frey, I have the great honor to participate in the Talk Back sessions after two of the performances to share my thoughts about the play’s scientific content.
The play consists of a series of scenes each of which represents a different interaction of the protagonists, Marianne and Roland, in various contrasting scenarios that could be playing out in different universes of the multiverse. The notion of a multiverse is based on a theory that there is a landscape which contains an infinite number of universes. The scenes alternate between witty and poignant, frivolous and weighted. Both the scientific allusions as well as the ethical decisions the characters encounter are relevant and provocative. The actors, Mel Marginet and Derek Leenhouts, authentically vary their portrayals to accommodate the ever shifting ambiance from scene to scene, from lighthearted to grave, from awkward to intimate, from warm to aloof, from casual to intense. Although the play follows only two individuals through the possible situations they could share, the pair draws you into their stories which we can relate to with the different relationships in our lives and the different roles we play with the people who populate our life. Using a clever device of parallel universes, the play paints a mosaic of nuanced experiences we all share on our own life adventures.
What is the scientific idea behind the multiverse, and could we ever experimentally detect it? A popular theory within the framework of string theory (the mathematically self-consistent theory that unifies all four forces by postulating the most elementary constituents are one-dimensional strings, as opposed to point particles) is the landscape. The landscape gives a physical framework in which the anthropic principle could be valid. This provides a possible solution for why there is a small non-vanishing cosmological constant (the parameter in the universe responsible for the universe’s observed accelerated expansion, a sort of negative pressure). The anthropic principle considers why the state of the universe is such that life can exist. The landscape argument suggests that there is a landscape of universes within a multiverse, and since we observe life in our universe, we happen to occupy one of the domains which supports life. However, there could be other universes with different flavors of string theory (with different degrees of symmetries) and hence physical laws which don’t support life. You can imagine these universes as expanding bubbles within the multiverse.
Is there a way we could detect whether we live in a multiverse? Stephen Feeney, Matt Johnson, Daniel Mortlock, and Hiranya Peiris asked just that in 2010 (see their initial papers on the arXiv, arXiv:1012.1995 and their longer paper, arXiv:1012.3667). The cosmic microwave background (CMB) (in one scene this is the subject that the character Marianne studies) is the relic radiation from the Big Bang. At the origin of the universe, space was small and radiation was very hot. As space expands, the Big Bang’s relic photons’ wavelengths stretch out, decreasing their energy. Today the CMB has stretched to millimeter wavelength and a temperature of 2.73 above absolute zero. The universe is bathed in this radiation; it is everywhere and can even interfere as noise to electronic signals (remember the static on old TVs? Some of that was due to the CMB). Feeney et al postulated that when the bubbles containing eternally inflating universes collide, they will produce edges or discontinuities in the temperature maps of the CMB. At the Perimeter Institute, I was talking to Matt Johnson and mentioned I had used the Canny algorithm as an edge detection algorithm for my research with identifying cosmic string signals in the CMB. My application of the Canny algorithm was simpler, since I could assume a flat two-dimensional sky, and his team adapted a more sophisticated Canny algorithm for their models as part of their search for the edges produced by colliding universe bubbles in the CMB. Although they have not detected evidence of bubble collisions yet, their approach could provide a promising means of searching for evidence of the multiverse in CMB data.
Another scientific concept in the play is that of the many worlds interpretation in quantum mechanics. This can be illustrated by the Schroedinger cat thought experiment. Traditionally, we think of the wavefunction (the function which describes the state) of the cat as being a superposition of the two states, alive and dead, at the same time. If you peek in the box, the act of observing the cat collapses the wavefunction to a single state, that of the cat either being alive or dead. In the many worlds interpretation, after you observe the cat, there is part of your wavefunction where you observe the cat to be alive and part of your wavefunction where you see her to be dead. So in the many worlds version, the observer’s wavefunction splits as well and becomes entangled with the cat’s. Marianne deftly integrates these quantum ideas into her dialogue, relating her experience through the lens of physics which shapes her thoughts.
The character of Marianne in Constellations is a young engaging woman, who happens to be a theoretical cosmologist. She deconstructs the stereotype of scientists being either older men or dowdy women. We need more fictional portrayals of hip women in STEM to provide role models! Women like Marianne who are young, brilliant, and sophisticated, much like the real-life London-based cosmologist, Hiranya Peiris. Cosmology is sexy, and it’s refreshing to see a fictional woman physicist who not only advances science but also defies the preconceived notions society has defined for women in science. Women in science can have lives outside their work and can be intriguing and vivacious.
The idea of the multiverse builds the structure for the play, Constellations, but its underpinnings are grounded in philosophy and are far from alienating. Instead of feeling removed from these characters and their journey, we are left feeling connected to them and their stories while recognizing the common elements that weave through our own narratives. In a sense, the play provides a microcosm through which we can examine our own encounters with other people and our own evolving selves. As Roland states in the play, honey bees enjoy a fleeting existence. And during their ephemeral lives, they live with intention and purpose, either to mate with the queen bee or to work. Compared to the time scale of the universe, our lives are on the scale of nanoseconds. But we are here. And we do have the purpose to explore. The universe. Art. Philosophy. Ourselves and our connections with others. And love.