Local quantum entropies are of utmost interest in characterizing quantum fields, many-body systems, and gravity. Despite their importance, being nonlinear functionals of the underlying quantum state hinders their theoretical as well as experimental accessibility. Here, we show that suitably chosen classical entropies of standard measurement distributions capture many features of their quantum...
Recent work has shown that communication channels between Unruh–DeWitt detectors are sensitive not only to the initial particle content of a quantum field but also to the spacetime history prior to the communication protocol. In particular, a cosmological expansion occurring before the protocol begins reduces the channel’s capacity. This implies that the noise experienced by the receiver...
The existence of zero-point modes, or the so-called vacuum fluctuations, is one of the fundamental predictions of quantum field theory. From an open quantum system perspective, they constitute an omnipresent and an unavoidable environment of a charged particle. In this talk I would like to discuss if such an environment can lead to observable decoherence and compare it with fundamental...
Recent results on electron tunneling across a potential barrier, inferred from experimental observations or obtained from theoretical models, have suggested superluminal or instantaneous barrier traversal times. We will argue, by linking the QFT property of microcausality to the wave-packet second quantized state that the tunneling dynamics is fully causal, precluding instantaneous or...
It is believed that quantum fluctuations of various fields including electromagnetic and gravitational fields are generated during inflation. On top of those, quantum fluctuations of ultralight axion fields could be generated. These fields can be naturally mixed in the history of the universe. Moreover, because of the rapid expansion of the universe, the quantum fluctuations lead to the...
Studies of extraction of entanglement from quantum fields usually consider probes that couple to independent degrees of freedom of the field, in an attempt to harvest entanglement. These studies usually rely on the specific properties of the probes and perturbative results, resulting in a nearly negligible extraction of entanglement. In this talk we will first quantify the distillable...
In this presentation we will discuss our work on the evolution of a quantum field subject to a time-dependent, confining potential well. In particular we focus on the entanglement dynamics in the process of the construction of a confined field in a finite region (that can be seen as the construction of an optical cavity) from the field vacuum in flat free space. Furthermore, we will discuss...
While there are many similarities between mechanics and field theory (both classical and quantum), there are also some fundamental conceptual differences. Examples include (i) the existence of derivatives in directions of 3-space (not to be confused with the configuration space directions), (ii) nonlocality of the evolution operator, (iii) different (and inequivalent) notions of "particle",...
In this talk, we define and characterize localized causal operations in a real scalar quantum field theory, and we will show that these operations exactly correspond to those satisfying various equivalent no-signalling conditions proposed in previous works. The simplicity of this characterization allows us to define a faithful quantifier of how much a map enables faster-than-light signalling...
The possibility of quantizing fields in neighborhood of arbitrary spacetime hypersurfaces, not necessarily of Cauchy nature, lies at the core of the so called General Boundary Formulation (GBF) of quantum theory. The GBF provides a novel perspective on quantum dynamics and offers the opportunity to address problems that are challenging (or even impossible) to solve within the standard...
The formalism of open quantum systems provides a way to derive evolution equations, called master equations, for a quantum system of interest that is coupled to an environment, without the need to solve the dynamics of the environment in detail. The starting point of this talk is a master equation for a scalar field as system of interest in an environment of quantised linearised gravity from...
Gravitationally Induced Entanglement (GIE) between two levitated objects in quantum states can investigates the quantum nature of the gravitational field in a tabletop experiment. To formally treat the entangling dynamics — both unitary and open — between superpositions of quantum states of matter entangled with a qubit, the Gaussian formalism of continuous-variable systems can be extended to...
