This glossary collects the central terms of the Frame-Budget Approach (FBA) — concise, operational, and cross-linked. It is meant as a working tool: while reading Parts I–X you can quickly look things up and follow “See also” links to connect the concepts.
How to use this glossary
- Quick lookup: click a term → short definition + cross-references.
- Read operationally: many terms are deliberately phrased as protocol/measurement concepts (what is distinguishable? what does an update cost?).
- Sources: “Source” points to the parts where the term is introduced/used.
Index (A–Z)
A
Sequence
In FBA, the primitive structure is an order of updates (“which step follows which?”) — not a presupposed time coordinate. A metric notion of time arises only through calibration.
- See also: Calibration, Minimal event, Proper time
- Source: Part I, Part II
Aging (A)
Operational quantity for the irreversible component of the internal budget along a worldline. Reversible contributions can carry proper time without increasing aging; dissipation increases aging.
- See also: Budget (irreversible), Thermodynamics, Proper time
- Source: Part I, Part VIII
B
Budget
Accounted quantity for the feasibility cost of a transition. Typically decomposed into internal (change of the system) and external (change of relations/location/order). A component may be irreversible.
- See also: Calibration, Proper time, Aging, Signal front
- Source: Part I
C
CPTP channel
An “admissible update” of a quantum state as a completely positive, trace-preserving process. CPTP channels provide the process language for kinematics and dynamics (including coupling to environments).
- See also: Dynamics, GKLS/Lindblad, Measurement
- Source: Part III, Part IV
E
Proper time (τ)
System-bound time quantity, operationally defined as the integrated internal budget flow along a worldline. Proper time arises through calibration of the internal budget.
- See also: Budget (internal), Sequence, Time dilation
- Source: Part I, Part II
F
Frame
A “state snapshot” recognized as the same within a chosen protocol (relative to resolution/protocol boundary). Frames are the operational comparison points for updates.
- See also: Minimal event, Distinguishability
- Source: Part I
Front / signal front
From budget positivity + calibration one obtains a maximum propagation front for influences/signals (light-cone logic). Not an extra postulate, but a consequence of cost rates/bounds.
- See also: Calibration, Locality, No-signalling
- Source: Part I, Part II, Part V
G
GKLS / Lindblad dynamics
Standard form for Markovian dynamics of open quantum systems. In FBA it serves as a bridge from the process language (channels) to dissipation, decoherence, and effective generators.
- See also: CPTP channel, Measurement, Aging
- Source: Part IV
K
Calibration
A mapping “budget ↔ measurable quantity”. Calibration turns accounting into testable physics: proper time from internal budget flow, front bounds from external cost rates, time dilation as redistribution of budget.
- See also: Budget, Proper time, Signal front
- Source: Part I, Part II
L
Locality
The principle that influences propagate only within neighborhoods determined by the budget/front constraints. In FBA, locality is operationalized as a consequence of signal-front logic.
- See also: Signal front, No-signalling, Spacetime
- Source: Part V
M
Measurement
A physical process that makes information from a system available to a protocol (and typically involves irreversibility/dissipation). In FBA it is embedded in the process language (channels/GKLS).
- See also: CPTP channel, GKLS, Aging
- Source: Part IV
Minimal event (ME)
The smallest update step that takes “same” to “different” within the chosen protocol. Minimal events are the “counting units” of the sequence.
- See also: Frame, Sequence
- Source: Part I
N
No-signalling
The constraint that information cannot be transmitted outside the admissible signal front. In FBA, no-signalling is anchored via budget and front bounds (local causal structure).
- See also: Signal front, Locality
- Source: Part V
P
Protocol boundary
A specification of resolution/decision rules according to which states count as “same” or “different”. Without a protocol boundary, “distinguishability” is not defined.
- See also: Frame, Minimal event, Distinguishability
- Source: Part I
R
Spacetime
An effective geometric description of causal structure and (calibrated) time measurement. In FBA, spacetime geometry is a derived structure emerging from budget flows and front logic.
- See also: Signal front, Locality, Gravity
- Source: Part V, Part VI
T
Thermodynamics
In FBA closely tied to irreversibility: dissipation and entropy production correspond to an irreversible budget component; this provides an operational bridge to the arrow of time and aging.
- See also: Aging, Budget (irreversible)
- Source: Part VIII
Time dilation
A relative change of clock rates (e.g., proper time vs. coordinate time) as a consequence of different budget distributions/flows. Connects to relativistic kinematics/gravity via suitable calibrations.
- See also: Proper time, Gravity, Minkowski
- Source: Part II, Part VI, Part IX
U
Distinguishability
An operational property relative to a protocol: two states are distinguishable if the protocol reliably classifies them as “different”. Distinguishability is the basis for frames and minimal events.
- See also: Protocol boundary, Frame, Minimal event
- Source: Part I
Z
Admissible dynamics
The set of allowed processes/updates under budget and consistency constraints. In quantum language: channels (CPTP) and generators (GKLS) as standardized classes of admissible dynamics.
- See also: CPTP channel, GKLS, Budget
- Source: Part III, Part IV