Arrow of time ≈ Arrow of time
View article
Dynamical Quantum Phase Transitions: A Geometric Picture Open
The Loschmidt echo is a purely quantum-mechanical quantity whose determination for large quantum many-body systems requires an exceptionally precise knowledge of all eigenstates and eigenenergies. One might therefore be tempted to dismiss …
View article
Arrow of Causality and Quantum Gravity Open
Causality in quantum field theory is defined by the vanishing of field commutators for spacelike separations. However, this does not imply a direction for causal effects. Hidden in our conventions for quantization is a connection to the de…
View article
Entanglement entropy of cosmological perturbations Open
We show that the entropy of cosmological perturbations originating as quantum vacuum fluctuations in the very early universe, including the contribution of the leading nonlinear interactions, can be viewed as momentum space entanglement en…
View article
Role of quantum coherence in the thermodynamics of energy transfer Open
Recent research on the thermodynamic arrow of time, at the microscopic scale, has questioned the universality of its direction. Theoretical studies showed that quantum correlations can be used to revert the natural heat flow (from the hot …
View article
Strong cosmic censorship: The nonlinear story Open
A satisfactory formulation of the laws of physics entails that the future evolution of a physical system should be determined from appropriate initial conditions. The existence of Cauchy horizons in solutions of the Einstein field equation…
View article
Timescales in the quench dynamics of many-body quantum systems: Participation ratio versus out-of-time ordered correlator Open
We study quench dynamics in the many-body Hilbert space using two isolated systems with a finite number of interacting particles: a paradigmatic model of randomly interacting bosons and a dynamical (clean) model of interacting spins-1/2. F…
View article
What is the entropy in entropic gravity? Open
We explore theories in which gravity arises as a consequence of entropy. We distinguish between two approaches to this idea: holographic gravity, in which Einstein’s equation arises from keeping entropy stationary in equilibrium under vari…
View article
Extended uncertainty principle for rindler and cosmological horizons Open
\n We find exact formulas for the Extended Uncertainty Principle (EUP) for the Rindler and Friedmann horizons and show that they can be expanded to obtain asymptotic forms known from the previous literature. We calculate the corrections to…
View article
Is Time's Arrow Perspectival? Open
We observe entropy decrease towards the past. Does this imply that in the\npast the world was in a non-generic microstate? I point out an alternative. The\nsubsystem to which we belong interacts with the universe via a relatively small\nnu…
View article
The Two-Time Interpretation and Macroscopic Time-Reversibility Open
The two-state vector formalism motivates a time-symmetric interpretation of quantum mechanics that entails a resolution of the measurement problem. We revisit a post-selection-assisted collapse model previously suggested by us, claiming th…
View article
Arrow of Time for Continuous Quantum Measurement Open
We investigate the statistical arrow of time for a quantum system being monitored by a sequence of measurements. For a continuous qubit measurement example, we demonstrate that time-reversed evolution is always physically possible, provide…
View article
Entanglement-Driven Cosmological Expansion (EDCE): Paper I The Geometric Cost of Irreversibility Open
We propose the Entanglement-Driven Cosmological Expansion (EDCE) theory, a unified quantum-cosmological framework that attempts to resolve the Cosmic Coincidence Problem by linking the emergence of the Arrow of Time to the expansion of spa…
View article
The arrow of time of brain signals in cognition: Potential intriguing role of parts of the default mode network Open
A promising idea in human cognitive neuroscience is that the default mode network (DMN) is responsible for coordinating the recruitment and scheduling of networks for computing and solving task-specific cognitive problems. This is supporte…
View article
Building the Arrow of Time… Over Time: A Sequence of Brain Activity Mapping Imagined Events in Time and Space Open
When moving, the spatiotemporal unfolding of events is bound to our physical trajectory, and time and space become entangled in episodic memory. When imagining past or future events, or being in different geographical locations, the tempor…
View article
Quantum asymmetry between time and space Open
An asymmetry exists between time and space in the sense that physical systems inevitably evolve over time, whereas there is no corresponding ubiquitous translation over space. The asymmetry, which is presumed to be elemental , is represent…
View article
Temporal irreversibility of neural dynamics as a signature of consciousness Open
Dissipative systems evolve in the preferred temporal direction indicated by the thermodynamic arrow of time. The fundamental nature of this temporal asymmetry led us to hypothesize its presence in the neural activity evoked by conscious pe…
View article
Today’s ecological relevance of Bergson-Einstein debate on time Open
The reflections on the nature of time in Relativity Theory will be hinted in reference to the new bridges recently proposed by Connes and by Rovelli's perspectival approach, two major steps towards a unification of quantum, thermodynamical…
View article
Observational Evidence for Entanglement-Driven Expansion VIII: The Thermodynamic Origin of the Big Bang and the Cyclic Universe Open
In this concluding paper of the Entanglement-Driven Cosmological Expansion (EDCE) series, we synthesize our previous findings into a unified cosmological framework. Using the “Phantom” Dark Energy parameters derived from DESI 2024 (w0 ≈−2.…
View article
Entropy Derived from Causality Open
The second law of thermodynamics, with its positive change of entropy for a system not in equilibrium, defines an arrow of time. Interestingly, also, causality, which is the connection between a cause and an effect, requests a direction of…
View article
Finite-time thermodynamics of fluctuations in microscopic heat engines Open
Fluctuations of thermodynamic quantities become non-negligible and play an\nimportant role when the system size is small. We develop finite-time\nthermodynamics of fluctuations in microscopic heat engines whose environmental\ntemperature a…
View article
Signature of a nonequilibrium quantum phase transition in the long-time average of the Loschmidt echo Open
We unveil the role of the long time average of Loschmidt echo in the\ncharacterization of nonequilibrium quantum phase transitions by studying sudden\nquench processes across quantum phase transitions in various quantum systems.\nWhile the…
View article
Statistical equilibrium in quantum gravity: Gibbs states in group field theory Open
Gibbs states are known to play a crucial role in the statistical description\nof a system with a large number of degrees of freedom. They are expected to be\nvital also in a quantum gravitational system with many underlying fundamental\ndi…
View article
Is the hypothesis about a low entropy initial state of the Universe necessary for explaining the arrow of time? Open
According to statistical mechanics, microstates of an isolated physical system (say, a gas in a box) at time t0 in a given macrostate of less-than-maximal entropy typically evolve in such a way that the entropy at time t increases with |t-…
View article
Entropy and Time Open
The idea that entropy is associated with the “arrow of time” has its roots in Clausius’s statement on the Second Law: “Entropy of the Universe always increases.” However, the explicit association of the entropy with time’s arrow arises fro…
View article
Entropic Bounds on Information Backflow Open
In the dynamics of open quantum systems, the backflow of information to the reduced system under study has been suggested as the actual physical mechanism inducing memory and thus leading to non-Markovian quantum dynamics. To this aim, the…
View article
Negative contributions to entropy production induced by quantum coherences Open
The entropy production in dissipative processes is the essence of the arrow\nof time and the second law of thermodynamics. For dissipation of quantum\nsystems, it was recently shown that the entropy production contains indeed two\ncontribu…
View article
In command of non-equilibrium Open
Living organisms and materials produced in the laboratory form ordered non-equilibrium states when part of the required energy is dissipated as heat.
View article
An autonomous quantum machine to measure the thermodynamic arrow of time Open
According to the second law of thermodynamics, the evolution of physical systems has a preferred direction, that is characterized by some positive entropy production. Here we propose a direct way to measure the stochastic entropy produced …
View article
Heat flow reversals without reversing the arrow of time: The role of internal quantum coherences and correlations Open
One of the stunning consequences of quantum correlations in thermodynamics is the reversal of the arrow of time, recently shown experimentally in [K. Micadei, et al., Nat. Commun. 10:2456 (2019)], and manifesting itself by a reversal of th…
View article
The Logic of the Past Hypothesis Open
I attempt to get as clear as possible on the chain of reasoning by which irreversible macrodynamics is derivable from time-reversible microphysics, and in particular to clarify just what kinds of assumptions about the initial state of the …