Krissia Zawadzki
Principal Investigator
Krissia holds a BSc in Computational Physics (2011) as well as an MSc (2014) and a PhD in Theoretical Physics (2018) from the University of São Paulo. After graduating, she collaborated with groups at Northeastern University (US), ICTP-SAIFR (BR) , Royal Holloway University of London (UK) and Trinity College Dublin (IRE) as a postdoctoral researcher. Currently, she is an assistant professor at the São Carlos Institute of Physics.
More about me
Professional self
My academic adventure started at the São Carlos Institute of Physics, in Brazil 🇧🇷, where I obtained my BSc, MSc and PhD. It has since taken me around the world ✈️ as a nomadic researcher. After a few postdocs, I returned to my alma mater as an assistant professor 👩🏫.
I am fortunate to have a wonderful group of fellows helping me in our various quests to unveil many-body entanglement! We named ourselves QuCoA 🍫, a title inspired by my passion for quantum correlations and the need to make a joke about my addiction to chocolate. Together, we are working 🦾 to answer questions that remain open in the many-body problem. Some of them are fundamental; others are driven simply by curiosity. Nonetheless, exploring them may help advance quantum sciences. So, wouldn’t you be tempted?
Personal self
Beyond my professional life, I enjoy drawing 👩🏻🎨, swimming 🏊🏻♀️, traveling 🧳, baking 🍰, attending heavy metal festivals 🎸, and I have a fondness for cats 🐈 and ice cream 🍦(actually gelato 😉).
If you attend one of my talks or lectures, you will see that am a big fan of Bitmojis! And, if you come over to visit me in São Carlos, it is very likely that you will be indulged with brigadeiros 🍬.
Brigadeiros
For those not familiar with this Brazilian delicacy, a nice definition is: brigadeiros are a strongly correlated state of cocoa and condensed milk. Are they entangled?
Well, to answer that question, one first has to build a minimal model for this system, including the preparation protocol. Let's make it a quantum thermodynamics problem. We start with the hamiltonian.
$$ H_{\textrm{brigadeiro}}(t) = H_{\textrm{cond-milk}} + H_{\textrm{cocoa}} + H_{\textrm{heat-bath}} + H_{\textrm{stirring}}(t), $$ where the first two terms contain all the degrees of freedom required to describe the system (sugar + milk and pure cocoa powder) before and after turning into brigadeiro. The third describes the heat bath which provides energy necessary for condensation, while the last is the external time-dependent drive associated with stirring, which both couples milk and cocoa and assists the transfer of heat.
If we know the initial state of the system -condensed milk+cocoa powder+bath- we have all the ingredients (🥁) and instructions to solve this problem. It is reasonable to assume that the state of the heat bath remains unchanged during the process. Of course, a more accurate description should include additional effects of the oven, the pan, etc, etc. But let's keep it simple.
One can then derive a master equation for the mixture (cocoa + condensed milk). Suppose that the effective dynamics is described by the Liouvillian master equation
$$\frac{d \rho_m}{dt} =\mathcal{L}_B\rho_m$$
where the state that appears represents the instantaneous state of the mixture.
By solving this equation and finding the steady-state -my beloved brigadeiro phase- one can determine whether condensed milk and cocoa are indeed entangled at the end of the preparation process. Just pick a suitable measure of entanglement for mixed states and see for yourself!
A possible future direction is to explore whether the Mpemba effect could accelerate the preparation of the brigadeiro phase. Maybe a variational quantum algorithm could provide an optimal protocol for the stirring control.