Can I get help finding this text and maths font for LaTeX?

I think this text and maths font, https://iopscience.iop.org/article/10.1088/2515-7639/abf0b5/pdf, see image below

Do you know of an easy way to find them, so I can use them for future projects?

thank you

There is a complex relationship with PDF text and Fonts so to take the core of your question

∇· B = 4πgδ(r).

• ∇ = CMBSY10
• · = CMSY10
• B = MinionLT-BoldItalic
• = = CMR10
• 4 = MinionLT-Regular
• π = CMMI10
• g = MinionLT-Italic
• δ = CMMI10
• etc. etc.

Where CM is ComputerModern, around 47 styles in total but the majority of plain text in that page is MinionLT-Regular.

Command Line tools can show a page teardown, perhaps broken down to character level. Often not that useful as it shows subsets by object number.

Poppler\poppler-22.04.0\Library\bin>pdffonts -f 7 -l 7 input.pdf
name                                 type              encoding         emb sub uni object ID
------------------------------------ ----------------- ---------------- --- --- --- ---------
OPVSPT+CMSY7                         Type 1C           Builtin          yes yes yes    107  0
VBXBEJ+MinionLT-Italic               CID TrueType      Identity-H       yes yes yes     90  0
KJURQA+MinionLT-Bold                 CID TrueType      Identity-H       yes yes yes     91  0
IXNNUR+MinionLT-Regular              CID TrueType      Identity-H       yes yes yes     92  0
PECOIF+CMR10                         Type 1C           Builtin          yes yes yes    109  0
MULJHB+MinionLT-BoldItalic           CID TrueType      Identity-H       yes yes yes     96  0
PUOMEI+MSBM10                        Type 1C           Builtin          yes yes yes     95  0
DLUNEF+CMMI10                        Type 1C           Builtin          yes yes yes     99  0
DGWJHV+CMBSY10                       Type 1C           Builtin          yes yes yes   1942  0
IEMQCU+CMSY10                        Type 1C           Builtin          yes yes yes    110  0
RVAVWH+esint10                       Type 1C           Builtin          yes yes yes    100  0
SXJKPE+CMR7                          Type 1C           Builtin          yes yes yes    210  0

</fill_text>
<fill_text colorspace="DeviceGray" color="0" transform="1 0 0 -1 72 72">
    <span font="DGWJHV+CMBSY10" wmode="0" bidi="0" trm="9.9999 0 0 9.9999">
        <g unicode="Γêç" glyph="nabla" x="229.208" y="-250.175" adv=".958"/>
    </span>
    <span font="IEMQCU+CMSY10" wmode="0" bidi="0" trm="9.9999 0 0 9.9999">
        <g unicode="┬╖" glyph="periodcentered" x="240.458" y="-250.175" adv=".277"/>
    </span>
    <span font="MULJHB+MinionLT-BoldItalic" wmode="0" bidi="0" trm="9.9999 0 0 9.9999">
        <g unicode="B" glyph="34" x="244.902" y="-250.175" adv=".616"/>
    </span>
    <span font="PECOIF+CMR10" wmode="0" bidi="0" trm="9.9999 0 0 9.9999">
        <g unicode="=" glyph="equal" x="253.28499" y="-250.175" adv=".777"/>
    </span>
    <span font="IXNNUR+MinionLT-Regular" wmode="0" bidi="0" trm="9.9999 0 0 9.9999">
        <g unicode="4" glyph="20" x="263.284" y="-250.175" adv=".48"/>
    </span>
    <span font="DLUNEF+CMMI10" wmode="0" bidi="0" trm="9.9999 0 0 9.9999">
        <g unicode="π" glyph="pi" x="268.08399" y="-250.175" adv=".57"/>
    </span>
    <span font="VBXBEJ+MinionLT-Italic" wmode="0" bidi="0" trm="9.9999 0 0 9.9999">
        <g unicode="g" glyph="71" x="274.14299" y="-250.175" adv=".413"/>
    </span>
    <span font="DLUNEF+CMMI10" wmode="0" bidi="0" trm="9.9999 0 0 9.9999">
        <g unicode="╬┤" glyph="delta" x="279.38398" y="-250.175" adv=".444"/>
    </span>
    <span font="PECOIF+CMR10" wmode="0" bidi="0" trm="9.9999 0 0 9.9999">
        <g unicode="(" glyph="parenleft" x="284.20698" y="-250.175" adv=".388"/>
    </span>
    <span font="MULJHB+MinionLT-BoldItalic" wmode="0" bidi="0" trm="9.9999 0 0 9.9999">
        <g unicode="r" glyph="82" x="288.09599" y="-250.175" adv=".384"/>
    </span>
    <span font="PECOIF+CMR10" wmode="0" bidi="0" trm="9.9999 0 0 9.9999">
        <g unicode=")" glyph="parenright" x="291.93598" y="-250.175" adv=".388"/>
    </span>
    <span font="DLUNEF+CMMI10" wmode="0" bidi="0" trm="9.9999 0 0 9.9999">
        <g unicode="." glyph="period" x="295.82499" y="-250.175" adv=".277"/>
    </span>
    <span font="IXNNUR+MinionLT-Regular" wmode="0" bidi="0" trm="9.9999 0 0 9.9999">
        <g unicode="(" glyph="8" x="468.55598" y="-250.175" adv=".37"/>
        <g unicode="2" glyph="18" x="472.25593" y="-250.175" adv=".48"/>
        <g unicode=")" glyph="9" x="477.05589" y="-250.175" adv=".37"/>

But for single query, "Editor Apps" like "Acrobat Pro" or cheaper can quickly itemize characters. Generally viewers such as "Reader" can only list the styles.

File: C:\Users\WDAGUtilityAccount\Desktop\SumatraPDF\Cayssol_2021_J._Phys._Mater._4_034007.pdf
Title: Topological and geometrical aspects of band theory
Subject: Journal of Physics: Materials, 4 (2021) 034007 doi: 10.1088/2515-7639/abf0b5
Author: J Cayssol,J N Fuchs
Created: 4/17/2021 4:01:00 AM
Modified: 6/21/2022 2:28:35 AM
Application: XeLateX with hyperref package
PDF Producer: XeLateX; modified using iText® 5.5.10 ©2000-2015 iText Group NV (AGPL-version)
PDF Version: 1.7
File Size: 4.15 MB (4,356,781 Bytes)
Number of Pages: 67
Page Size: 8.26 x 11.69 in (A4)
   
Fonts: Academicons (TrueType (CID); Identity-H; embedded)
ArialUnicodeMS (TrueType (CID); Identity-H; embedded)
CMBSY9 (Type1; embedded)
CMBSY10 (Type1; embedded)
CMBX9 (Type1; embedded)
CMBX10 (Type1; embedded)
CMEX10 (Type1; embedded)
CMMI5 (Type1; embedded)
CMMI6 (Type1; embedded)
CMMI7 (Type1; embedded)
CMMI8 (Type1; embedded)
CMMI9 (Type1; embedded)
CMMI10 (Type1; embedded)
CMMIB7 (Type1; embedded)
CMMIB8 (Type1; embedded)
CMMIB10 (Type1; embedded)
CMR5 (Type1; embedded)
CMR6 (Type1; embedded)
CMR7 (Type1; embedded)
CMR8 (Type1; embedded)
CMR9 (Type1; embedded)
CMR10 (Type1; embedded)
CMSY5 (Type1; embedded)
CMSY6 (Type1; embedded)
CMSY7 (Type1; embedded)
CMSY8 (Type1; embedded)
CMSY9 (Type1; embedded)
CMSY10 (Type1; embedded)
dsrom12 (Type1; embedded)
esint10 (Type1; embedded)
EUFB10 (Type1; embedded)
EURM10 (Type1; embedded)
Helvetica (Type1; Ansi)
Helvetica-Bold (Type1; Ansi)
Helvetica-Oblique (Type1; 
ITCFranklinGothicStd-BkCd (Type1 (CID); Identity-H; embedded)
ITCFranklinGothicStd-DmCd (Type1 (CID); Identity-H; embedded)
MinionLT-Bold (TrueType (CID); Identity-H; embedded)
MinionLT-BoldItalic (TrueType (CID); Identity-H; embedded)
MinionLT-Italic (TrueType (CID); Identity-H; embedded)
MinionLT-Regular (TrueType (CID); Identity-H; embedded)
MinionLT-Semibold (TrueType (CID); Identity-H; embedded)
MSAM7 (Type1; embedded)
MSAM10 (Type1; embedded)
MSBM5 (Type1; embedded)
MSBM7 (Type1; embedded)
MSBM10 (Type1; embedded)